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Different types of cleaners used in grain processing and their performance evaluation

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PRESENTED BY:
ARSHPREET KAUR
B.TECH.
(AGRI. ENGG. AND TECH.)

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CLEANING
1. Scalper
2. De awner
3. Fanning mill
4. Air screen cleaner
5. Specific Gravity separator
6. Indented cylinder s...

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Scalper
 A scalper can be used to rough
clean seed when trash content is
high.
 The scalper basically consists of a
vibr...

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Different types of cleaners used in grain processing and their performance evaluation

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A detailed description of different types of cleaners used in grain processing and evaluation of their performance

A detailed description of different types of cleaners used in grain processing and evaluation of their performance

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Different types of cleaners used in grain processing and their performance evaluation

  1. 1. PRESENTED BY: ARSHPREET KAUR B.TECH. (AGRI. ENGG. AND TECH.)
  2. 2. CLEANING 1. Scalper 2. De awner 3. Fanning mill 4. Air screen cleaner 5. Specific Gravity separator 6. Indented cylinder separator 7. Cyclone Separator 8. Pneumatic separator 9. Inclined draper 10. Electrostatic separator 11. Magnetic separator
  3. 3. Scalper  A scalper can be used to rough clean seed when trash content is high.  The scalper basically consists of a vibrating or rotating screen or sieve.  The screen perforations are large enough to allow the rough seed to pass through readily while large inert material is scalped off and removed from the seed lot.  Some of the high moisture particles may be removed  Normally much higher output than fine cleaning
  4. 4. De awner  Before air screen cleaner  Optional, it can be bypassed  Seed flows much better in rest of cleaning process  Important when mechanical planting machines are used  May be important for breaking dormancy in some species
  5. 5. Fanning Mill  Screen cleaners that employ an air blast to assist in cleaning is known as fanning mill. Though  these are used for cleaning but these are not effective as regards to density and if the materials have the  same or nearly the same shape. Here in addition to the aspirating fan used to draw air through the  material fed on 1st screen unit, another fan is used to force the air through the product after fine grading
  6. 6. AIR SCREEN CLEANER  A common air screen cleaner for processing seed uses two air blasts and two screens.  The first air system removes dust and light chaff before the seed reaches the first screen.  The first screen allows the good seed to drop onto the second screen. The large foreign material rides over the first screen and is discarded.  The second screen is a grading screen  Uses three cleaning systems; aspiration, scalping screen and grading lower screen  Classified into two types based on the movement of the screening surface • Vibratory screen cleaner • Rotary screen cleaner
  7. 7. Vibratory screen cleaner  Screening unit is composed of double or multiple screens.  Screens are tightened together and suspended in such a manner that these have horizontal oscillating and slightly vertical motion.  The slope of the screen is adjustable to control the rate of forward travel of the grain  To avoid clogging, the screens are fitted with brush Two screen m/c fitted with aspirator to suck the lighter materials  Coarse impurities are screened off by upper screen Fine impurities are screened off by lower screen Grains are again cleaned by upward draft of air in the ascending separator  During this process, remaining lighter impurities and shriveled grains are sucked away  Lighter impurities are removed by Cyclone separator
  8. 8. Rotary air screen cleaner  Has normally circular decks  Motion is circular in horizontal plane  Either single or double drum  Consists of a rotary screen, aspirator and hopper  Sound grains pass through the screen perforation into the center of the screen drum. Oversized material is retained above and pass out through an outlet.  Sound grains come out at the center side of the drum rotating at low speed and fall onto the vibratory screen which remove the dirt particles  Light impurities are sucked away by the aspirator  Cleaned grains are discharged through the discharge chute
  9. 9. Specific Gravity Separator
  10. 10. Cyclone Separator  The cyclone separator is used extensively in processing and other operations as a device for collecting end product.  It is also frequently used in connection with pneumatic conveying of products  and wastes from processing. These are used for removal of particle about 10 μm or more in diameter from the air stream.  These are used for separating particle from liquid droplets from gases.  Cyclones are basically used for cleaning air or for settling the dust particles etc.  It is used in combination with some other machines e.g. as you have seen with hammer mill/aspirating column etc.
  11. 11. Pneumatic Separator  The aspirating column is the equipment which is used for this purpose.  The material is fed from the duct provided at the side.  The lighter particles have less terminal velocity whereas grains and other heavy particles have more value of terminal velocity.  This difference in terminal velocity provides the basis for the separation of materials.  This is best suited for removing very small sized and immature grains from healthy grains.
  12. 12. Inclined Draper  The separations by inclined belts draper takes place due to difference in shape and surface texture of the material.  This technique of separation is used when all other methods fail.  The mixture to be separated is fed over the centre of an inclined draper belt moving direction.  The round and smooth grains roll or slide down the draper at faster rate than the upward motion of the belt and these are discharged in a hopper.  The flat shape or rough surface particles are carried to the top of the inclined draper and dropped off into another hopper.  The belts of different degrees of roughness may be used as a draper for separate materials.  Feed rate, speed of draper and angle of inclination are other factors for effective separation of dissimilar materials.
  13. 13. Electrostatic Separator  Electrostatic beneficiation allows for separations based on differences in surface chemistry (work function) or dielectric properties.  In some instances, these separations would not be possible using size or density separations alone.  Electrostatic separation systems operate on similar principles. All electrostatic separation systems contain a system to electrically charge the particles, an externally generated electric field for the separation to occur in, and a method of conveying particles into and out the separation device.  In all electrostatic units, high potentials are used to give practical forces of attraction. Since  electrostatic charges leak away rapidly in moist air, so equipment & air must be dry.
  14. 14. Magnetic Separator  Magnetic Separators are most commonly used to separate iron or steel materials that have a low magnetic attractivity.  Since magnetic separators have a wide variety of functions, several devices are available.  A simple method is of keeping a magnet close to the contaminated material as it passes along a conveyor.  The iron and steel particles are collected on the face of magnet and removed periodically.  Another method is using a magnetic pulley in a belt conveyor. The magnet will attract the iron or steel particles and therefore deflected to one side  Magnetic separator performs separations on the basis of surface texture and stickiness properties of the grains.  Since the grains does not contain any free iron, therefore are not attached by the magnet.

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