Лекція №1

Lecture 2Lecture 2

General concept about machinesand equipment.General concept about machinesand equipment.

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

Plan

1.General definition about machinesand equipment.

2.Processes of comminution.Characteristics.

3.Equipment for milling.

4.Processes of sifting. Equipment forsifting.

5.Processes of mixing. Equipment formixing.

Comminution – is a process of reductionof particle size of substance by mechanicalinfluence.Comminution – is a process of reductionof particle size of substance by mechanicalinfluence.

Motivation for particle size reduction:Motivation for particle size reduction:

increase specific surface of substances,increase specific surface of substances,

increase the free surface energy of crushedsubstances,increase the free surface energy of crushedsubstances,

significantly increase the speed of chemical anddiffusion processes,significantly increase the speed of chemical anddiffusion processes,

strengthen the pharmacological activity ofsubstances.strengthen the pharmacological activity ofsubstances.

Comminution is characterized bythe symbol index –”i” - the degree ofcomminution of substances.“I” equal ratio of the diameter ofpieces of material to the milling (D) toparticles diameter after ones (d).Comminution is characterized bythe symbol index –”i” - the degree ofcomminution of substances.“I” equal ratio of the diameter ofpieces of material to the milling (D) toparticles diameter after ones (d).

i = D / di = D / d

Types of milling in depend on degreeof comminution(in haw much times the particles size wasreduced):Types of milling in depend on degreeof comminution(in haw much times the particles size wasreduced):

1.Great (large) – in 2-6 times;1.Great (large) – in 2-6 times;

2.Medium - up 6-10 times;2.Medium - up 6-10 times;

3.Fine - at 10-50 times;3.Fine - at 10-50 times;

4.Micro fine - in 50-100 times;4.Micro fine - in 50-100 times;

5.Super fine - thin (colloidal) – in 100-10000 times.5.Super fine - thin (colloidal) – in 100-10000 times.

Classification equipment formilling:Classification equipment formilling:

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

1.Cutting machine1.Cutting machine

2.Attrition machine2.Attrition machine

3.Compression machine3.Compression machine

4.Impact machine4.Impact machine

5.Impact - Centrifugal machine5.Impact - Centrifugal machine

Classification equipment formilling:Classification equipment formilling:

By the degree of comminution:1. crushers:By the degree of comminution:1. crushers:

for great, medium, fine milling;2. mills:for great, medium, fine milling;2. mills:

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

Classification equipment formilling:Classification equipment formilling:

By the mechanism used to break theparticles:By the mechanism used to break theparticles:

1.Disc1.Disc

2.Boll2.Boll

3.Rotor3.Rotor

4.Hammer4.Hammer

5.Rollers and others5.Rollers and others

Requirements for the millingprocess:

1.Substances must has initial itscomposition and pharmacologicalproperties during the milling process;

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

3.Prevent formation of dust (sealedenclosures);

4.Appropriate moisture of material;

5.The use of sequence connectedcrushing-milling machines.

Parameters for choosing optimal type ofmachines:

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

2.The total amount of material for milling

4.Physical and chemical properties ofmaterial for milling

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

Grass cutting and straw cutting (grass, stalks).

Root cutting with the guillotine knife - for grindingroots, bark.

Drum straw cutting - for grinding dry medicines.

Knife mill - for milling volume materials, containingcellulose

Motorized soft meat grinder - for fresh herbaldrugs, animal raw materials

Crushes machines which areused 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 - CENTRIFUGALMILLS:IMPACT - CENTRIFUGALMILLS:

Hammer millHammer mill

DysmembratorDysmembrator

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 milledby acting of own weight:Mills, in which material are milledby acting of own weight:

Mills Continuous actionMills Continuous action

Mills periodic actionMills 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(RPA)Rotor - Pulsating apparatus(RPA)

Work of Jet mills

Jet mills

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

Sifting(Sorting, Screens) -is process department more largeor more small particles ofprimary mass separation loosematerials on separate fractionthat differ form and size.Sifting(Sorting, Screens) -is process department more largeor more small particles ofprimary mass separation loosematerials on separate fractionthat differ form and size.

Factors what affect onprocess of Sifting :Factors what affect onprocess of Sifting :

1.Shape and size of sieves1.Shape and size of sieves

2.Thickness of material layer on sieve2.Thickness of material layer on sieve

3.Humidity of material3.Humidity of material

4.Movement speed of materials on the sieve4.Movement speed of materials on the sieve

5.Nature of movement and length of waymaterial5.Nature of movement and length of waymaterial

6.Work Speed of sifting6.Work Speed of sifting

Classification sieves depend on wayof make:Classification sieves depend on wayof make:

1.Wicker sieve - by binding thin filaments or wires,with silk, steel and others. Filaments are easilyextracted and not strong, although cheap.1.Wicker sieve - by binding thin filaments or wires,with silk, steel and others. Filaments are easilyextracted and not strong, although cheap.

2.Stamped sieve - by punching metal plate with theformation of frequent round, oval or squareholes. They are very strong and widely used inindustry, but have rather large holes, so are notsuitable for small particles.2.Stamped sieve - by punching metal plate with theformation of frequent round, oval or squareholes. They are very strong and widely used inindustry, but have rather large holes, so are notsuitable for small particles.

3.Combination – by combination metal plates.They are very strong, but have low productivity.3.Combination – by combination metal plates.They are very strong, but have low productivity.

Classification sieves depend onnature of movementClassification sieves depend onnature of movement

1.Sieves, rotary - a cylindrical drum sieve, which isset at an angle. It consists of sections of sieveswith different size holes that can differentiatebetween material in size.1.Sieves, rotary - a cylindrical drum sieve, which isset at an angle. It consists of sections of sieveswith different size holes that can differentiatebetween material in size.

2.Sieve that swing - is installed on the box springrests at an angle to the horizontal 7-14.2.Sieve that swing - is installed on the box springrests at an angle to the horizontal 7-14.

3.Vibration sieve - the structure is the same as insieve that swing , but have a great frequencyvibrations - vibrations.3.Vibration sieve - the structure is the same as insieve that swing , but have a great frequencyvibrations - vibrations.