Air Separator

Separation

Is the division of a material stream into two separate streams using air as the carrying medium

Static Separator

Dynamic Separator

Main characteristic Static Main characteristic Static separatorseparator

No rotating parts are required for the separation

Cyclone and the grit separator

Typical Static Separator

Main characteristic Dynamic separator

Rotating parts are required for the separation

The fineness of the product can be changed by adjusting the speed of the rotating part

Typical Dynamic Separator

Mechanical air separator

Cyclone air separator

Dynamic separator for air swept ball mills & roller mill

Mechanical air separator and the cyclone air separator are used as separating units in grinding circuit mill bucket elevator mills.

Raw meal

Air separators are applied in :

Clinker & coal grinding circuits

Seprator Feed A

Seprator Finish F

Seprator Tail G

Fig 1

Separator as independent unit

Seperator Feed A

Separator Finish FSeparator Tail G

Original Feed M

Mill Discharge

Air SeparatorClosed Circut with one Separator

Fig 2

Seperator Feed A

Separator Finish F

Separator Tail G

Original Feed M

Mill Discharge

Air Separator - Closed Circutwith two Separator Series

Fig 3

S epa ra to r 1

S epa ra to r 2

Seperator FeedA

Separator Finish F

Separator Tail G

Original Feed M

Mill Discharge

Air Separator - Closed Circutwith two Separator Parallel

Fig 4

S epa ra to r 1 S epa ra to r 2

The advantage of installing separator(s) in grinding circuit are :

Rapid change to various product qualities

More regular fines control of product

Less sensitive to variations of mill feed material

Possibility of cooling & drying in separator

Reduced power consumption for very fine products

Increased capacity of grinding plant

Typical Arrangement of air separator

Centrifugal force Fc

Principle of separation

Gravity force FG

Assume particle of spherical shape

Force acting upon this particle

Uplifting force FU

Fc = Centrifugal Force

Fu = Uplifting Force

Fg = Gravity Force

Fu

Fg

Principle of Separation

The operation of air separator is based on the following principles

The action of an air current of certain velocity upon a mass-particle is proportional to the surface presented by this particle to the air current, thus to the square of the mean dimensions of the particle.

The action of the force of gravity upon a mass-particle is proportional to the volume, thus to the cube of the mean dimensions of the particle.

The effect of the force of gravity increase faster than that of an air current of constant velocity

The operation of air separator is based on the following principles

The effect of the force of gravity increase faster than that of an air current of constant velocity

If these two forces are concurrent, the force of gravity will prevail over the effect of the air current as particle dimensions increase.

Main characteristic Static separator

No rotating parts are required for the separation

Air is the conveying media for introducing feed material to the separator

The separator performs only the separating function and not the collection function of the fines

Characteristics of Dynamic Separator

Rotating parts are required for the separation

Only conventional types of dynamic separating are generating the separating air by means of fans which are part of the separator internal system

Only conventional types the separation of both of fine and coarse material take place inside the separator

Application of Mechanical Air separator

Separating unit in grinding circuit with bucket elevator

Separating unit in air-swept mills

Sturtevant Type

Separator

Cyclone Air Separator

Advantages of separating and precipitation

Specific load of separating zone can be increased which gives greater separation capacities up to 500 t/h of fine material

Variation in the separator feed don’t affect the fineness of the product, so the quality of the fines remain unchanged

Alteration of the product’s fineness can be achieved by changing the revolutions of the auxiliary fan as well as changing the circulating air volume through adjustment of the blower or the damper

Air Separator :

High Efficiency Separator

The week points of Mechanical Air Separator

The amount of separating air can not be adjusted sufficiently

In larger units, the distribution of feed is not proper in the separating zone.

The separation of the fine material from the separating air is deficient

The adjustment range of the product fineness is limited

The advantages of high efficiency separators

Reduction in specific power consumption

Improvement in product quality

Increase in grinding capacity

Reduction in cement temp.

Wider adjustment range in view of product fineness

High efficiency separators

High efficiency separator with separation by vertical air flow

Sepax Separator

Advantages of Sepax separators

Separate discharge of broken and worn grinding media, this reduce the clogging tendency in mill partition diagram

The suspended material flows into the separator via vertical guide vanes

Selection of cyclone

air Separator :

Fig 14Grinding System - Air Sw ep t Mill

Fig 15

Grinding System