Mixers for cohesive solids

1. MIXERS
FOR
COHESIVE
SOLIDS

2. 2
 Appropriate contact
 High viscosity
 Mixing is by combination of low speed
 Shear
 Smearing
 Wiping
 Folding
 Stretching
 compressing
 Mixer have
 high power consumption
 Cooling is required
Mixers for cohesive solids

3. DIFFERENT TYPES OF
MIXERS

4. Different types of mixers are:
1. Change-Can mixer
2. Kneaders
3. Dispersers
4. Masticators
5. Continuous kneaders
6. Mixer extruders
7. Mixing rolls
8. Muller and pan mixers
9. Pug mills

5. 5
1. Change-Can Mixers
 For viscous liquids and light pastes as:
 Food processing
 Paint manufacturing
 5 to 100 gal. in size
 Change-Can mixer are:
1. Pony mixer
2. Beater mixer

6. 6
1. Pony mixers
 Agitator consist of vertical blades held on rotating head
positioned near the wall of the can
 Blades are slightly twisted
 Agitator is mounted eccentrically
 Can rest on a turn table driven in direction opposite to that of
agitator
 All the material in the can is brought to the blade to be mixed
 When mixing is completed –blades are cleaned and can is
replaced
 BATIDORA_PONY_MIXER_500.mp4

7. Change Can Mixer (Pony Mixer)

8. 8
2. Beater mixers
 Can or vessel is stationary
 Agitator has a planetary motion
 Visits all parts of vessel
 Beaters are shaped to pass with close clearance over the side &
bottom of mixing vessel

9. Change Can Mixer (Beater)

10. 10
Kneaders
 Kneading – “squashing the mass flat, folding it over on
itself and squashing it once more”
 Also tear the mass apart and shear it between a moving
blade & a stationary surface.
 For deformable & plastic solids
 Large energy requirements
 Kneading_Mixing_Machine.pdf
 KNEADER.mp4

11.  It is heavier in construction and draws more power than a
kneader it works on additives & coloring agent into split
material.
 25_hp_Cowles_High_Speed_Disperser_#3497.mp4
 dispersion-kneader-machinery.pdf
Disperser

12.  A masticator is still heavier & draw even more power it can
distigrate scrap rubber & compound the toughest plastic
masses.
 Masticators are often called intensive mixer.
• Masticator Mixer with Screw Discharge.mp4
Masticators

13. 13
Banbury mixer
 Heavy duty two-arm mixer
 30 to 40 rpm
 Solids enter from top and discharge from bottom
 Applications:
 Compound rubber and plastic solids
 Masticate crude rubber
 Make water dispersion and rubber solution
 Shorter time and small batches
 Cooling is done by:
 Water spraying on walls
 Circulating through hollow agitator shaft

14. Banbury Mixer
Bainite_Automated_Turnkey_Mixin
g_Line_-_Saves_Labor.mp4

15. 15
Design of Blades
 Sigma blade:
 Used for general purpose kneading
 Edges are serrated to give a shredding action
 S-type Double-naben (fish-tail blade):
 Effective with heavy plastic materials
 develop high shear force
 Z-type Disperser blade:
 Heavier and develop high shearing forces
 Disperse powders or liquids into rubbery masses.

16. Kneader
(Sigma Blades)

17. Kneader
(Sigma Blades)

18. Double Naben Blades Z-type Disperser blade

19. 19
Continuous Kneaders
 Continuous operation
 deals light to fairly heavy materials (heavy, stiff, or gummy materials)
 consist of
 Single horizontal shaft
 Slow in motion
 Rows of teeth on shaft arranged in spiral pattern
 Stationary teeth on the wall of casing
 Close clearance between dynamic and stationary teeth
 Shaft turns and also reciprocates in the axial direction
 Several tons per hour

20. 20

21. 21
Mixer Extruders
 The discharge of continuous kneader is restricted by covering it
with an extrusion die
 Pitched blades of the rotor build up considerable pressure in the
material
 Material is cut and folded and subjected to additional shear
 Contain one or two horizontal shafts, rotating but not
reciprocating , carrying blades set in a helical pattern.
 Pressure is built by reducing the pitch of helix or by reducing the
diameter of chamber or both
 Continuously mix, compound, and work thermoplastics, clays, and
other hard-to-mix materials.
 Heating jacket is provided.

22. Mixer Extruder

23. 23
Mixing Rolls
 Smooth metal rolls at variable speeds
 For pastes & deformable solids to intense shear
 3 to 5 horizontal rolls in vertical stack
 Material moves from slower to faster ones
 Batch roll mills has two rolls set in horizontal plane and require
long mixing time and attention
 Used for dispersing solids in rubber and plastic materials
Mixing Rolls

24. Mixing Rolls

25.  Medium-speed
 Muller-types mixer for batch operation.
 Small-to medium sized sand partical
 Most difficult mixing
 Features:
1. Good mixer for batch of heavy solids.
2. Energy efficiency.
 muller mixer pan type.mp4
Muller Mixer

26. QUESTIONS???