Lecture Lecture 22

General concept about General concept about machines and equipment. machines and equipment.

Comminution (milling, grinding), grinding), sifting, mixing. sifting, mixing.

Plan

1. General definition about machines and equipment.

2. Processes of comminution. Characteristics.

3. Equipment for milling.4. Processes of sifting. Equipment for

sifting.5. Processes of mixing. Equipment for

mixing.

Comminution – is a process of Comminution – is a process of reduction of particle size of reduction of particle size of

substance by mechanical substance by mechanical

influence.influence. Motivation for particle size reduction: increase specific surface increase specific surface of of

substancessubstances,, increase the free surface energy of increase the free surface energy of

crushed substancescrushed substances,, significantly increase the speed of significantly increase the speed of

chemical and diffusion processes,chemical and diffusion processes, strengthen the pharmacological strengthen the pharmacological

activity of substancesactivity of substances..

ComminutionComminution is characterized by is characterized by the symbol index –”i” - the degree of the symbol index –”i” - the degree of

comminution of substances. comminution of substances. “I” equal ratio of the diameter of “I” equal ratio of the diameter of

pieces of material to the milling (D) to pieces of material to the milling (D) to particles diameter after ones (d). particles diameter after ones (d).

i = D / di = D / d

Types of milling in depend on degree Types of milling in depend on degree of comminution of comminution

(in(in haw much times the particles size was haw much times the particles size was reducedreduced))::

1.1. Great (large) – in 2-6 times; Great (large) – in 2-6 times;

2.2. Medium - up 6-10 times; Medium - up 6-10 times;

3.3. Fine - at 10-50 times; Fine - at 10-50 times;

4.4. Micro fine - in 50-100 times; Micro fine - in 50-100 times;

5.5. Super fine - thin (colloidal) – in Super fine - thin (colloidal) – in 100-10000 times. 100-10000 times.

Classification equipment for Classification equipment for milling: milling:

By the way of milling: By the way of milling:

1.1. Cutting machine Cutting machine

2.2. Attrition machine Attrition machine 3. Compression machine machine

4.4. Impact machine Impact machine

5.5. Impact - Centrifugal machineImpact - Centrifugal machine

Classification equipment for Classification equipment for

milling: milling:

ByBy the degreethe degree of of comminutioncomminution::

1.1. crushers: crushers:

for for greatgreat, , medium,medium, fine fine milling;milling;

2. mills2. mills::

for micro fine, superfine (for micro fine, superfine (colloidcolloid)) milling milling..

Classification equipment for Classification equipment for milling: milling:

By the By the mechanism used to break the particles: :

1.1. Disc Disc 2.2. Boll Boll 3.3. Rotor Rotor 4.4. Hammer Hammer 5.5. Rollers and othersRollers and others

Requirements for the milling process: 1. Substances must has initial its

composition and pharmacological properties during the milling process;

2. Periodically to remove enough milled particles from the sphere of comminution;

3. Prevent formation of dust (sealed enclosures);

4. Appropriate moisture of material; 5. The use of sequence connected

crushing-milling machines.

Parameters for choosing optimal type of

machines:

1. Initial size of the material and desirable size of final product

2. The total amount of material for milling

3.

4. Physical and chemical properties of material for milling

Cutting machine are used to comminution herbal drug that has a fibers structure.

Grass cutting and straw cutting (grass, stalks). Root cutting with the guillotine knife - for grinding

roots, bark. Drum straw cutting - for grinding dry medicines. Knife mill - for milling volume materials, containing

cellulose Motorized soft meat grinder - for fresh herbal

drugs, animal raw materials

Crushes machines which are used for milling solid materials: Cheek and jaw mill

Rollers mill

Cone mill

Hammer mill

Disk mill (Excelsior)

Jaw mill type shock

Grasscutting

Grasscutting

Cutting mill

Rollers mill

1,2 - rolls

3 - spring

Rollers mill

Disk mill (Excelsior)

IMPACT - IMPACT - CENTRIFUGAL MILLS: CENTRIFUGAL MILLS:

Hammer millHammer mill

DysmembratorDysmembrator

Disintegrator Disintegrator

Hammer mill

1 - rotor;

2 - hammer ;

3 - corps;

4 - plates.

Hammer mill

Hammer mill

Disintegrator

Machines for fine milling:Machines for fine milling:

Drum mills:Drum mills: Ball mills Ball mills Rod mills Rod mills Mills, in which material are milled Mills, in which material are milled

by acting of own weight: by acting of own weight: Mills Continuous action Mills Continuous action Mills periodic actionMills periodic action

Ball mill

Ball mill

Work of Ball mill

Machines for Superfine milling : Machines for Superfine milling :

Vibration mills Vibration mills Jet mills Jet mills Colloidal mills:Colloidal mills: Rotor - Pulsating apparatus Rotor - Pulsating apparatus

(RPA) (RPA)

Work of Jet mills

Jet mills

Equipment for Colloidal milling (vibration-cavitation mill, Conical mill )

Sifting Sifting (Sorting, Screens) - (Sorting, Screens) -

is process department is process department more large or more more large or more small particles of small particles of

primary mass separation primary mass separation loose materials on loose materials on

separate fraction that separate fraction that differ form and size. differ form and size.

Factors what affect on Factors what affect on process of Sifting : process of Sifting :

1.1. Shape and size of sievesShape and size of sieves

2.2. Thickness of material layer on Thickness of material layer on sievesieve

3.3. Humidity of materialHumidity of material

4.4. Movement speed of materials on Movement speed of materials on the sieve the sieve

5.5. Nature of movement and length of Nature of movement and length of way materialway material

6.6. Work Speed of Work Speed of siftingsifting

Classification sieves Classification sieves depend on way of makedepend on way of make:: 1.1. Wicker sieve - by binding thin filaments Wicker sieve - by binding thin filaments

or wires, with silk, steel and others. or wires, with silk, steel and others. Filaments are easily extracted and not Filaments are easily extracted and not strong, although cheap. strong, although cheap.

2.2. Stamped sieve - by punching metal Stamped sieve - by punching metal plate with the formation of frequent plate with the formation of frequent round, oval or square holes. They are round, oval or square holes. They are very strong and widely used in industry, very strong and widely used in industry, but have rather large holes, so are not but have rather large holes, so are not suitable for small particles. suitable for small particles.

3.3. Combination – by combination metal Combination – by combination metal plates. They are very strong, but have plates. They are very strong, but have low productivity.low productivity.

Classification sieves depend Classification sieves depend

on nature of movement on nature of movement 1.1. Sieves, rotary - a cylindrical drum sieve, Sieves, rotary - a cylindrical drum sieve,

which is set at an angle. It consists of which is set at an angle. It consists of sections of sieves with different size sections of sieves with different size holes that can differentiate between holes that can differentiate between material in size.material in size.

2.2. Sieve that swing - is installed on the box Sieve that swing - is installed on the box spring rests at an angle to the horizontal spring rests at an angle to the horizontal 7-14.7-14.

3.3. Vibration sieve - the structure is the Vibration sieve - the structure is the same as in sieve that swing , but have a same as in sieve that swing , but have a great frequency vibrations - vibrations.great frequency vibrations - vibrations.

Vibration sieve

Mixing is process which ia used Mixing is process which ia used for achievement uniformity of for achievement uniformity of

mixtures.mixtures.

Classification of mixers:Classification of mixers:

1.1. Mixers with rotating bladesMixers with rotating blades

2.2. Mixers with rotating corpsMixers with rotating corps

3.3. Circulation mixers which contains Circulation mixers which contains cone that rotates on a vertical axiscone that rotates on a vertical axis

4.4. Mixers with fluidized layer Mixers with fluidized layer ((material is thrown up by the air material is thrown up by the air pressurepressure).).

Mixer with rotating corps Mixer with rotating corps PattersonPatterson--Kelley Kelley

Mixer with rotating corps Mixer with rotating corps PattersonPatterson--Kelley Kelley

Mixer with rotating corps Mixer with rotating corps Ambica Boiler & Fabricators Ambica Boiler & Fabricators

Mixer with rotating blades Mixer with rotating blades Ambica Boiler & Fabricators Ambica Boiler & Fabricators

Mixer with continuous Mixer with continuous actionaction

Mixer - "Drunk barrel"Mixer - "Drunk barrel"

Thank you for your attention