This document discusses different types of mixers used for cohesive solids. It describes change-can mixers, kneaders, dispersers, masticators, continuous kneaders, mixer extruders, mixing rolls, muller and pan mixers, and pug mills. Change-can mixers include pony mixers and beater mixers. Kneaders work through folding, shearing, and tearing actions. Continuous kneaders and mixer extruders provide continuous mixing and extrusion. Mixing rolls intensively shear materials between rotating rolls. Muller mixers are suitable for batch mixing of heavy solids. Pugmills continuously mix and move materials through a chamber with helical blades.

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

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

11. ➢ It is heavier in construction and draws more power than a
kneader it works on additives & coloring agent into split
material.
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.
Masticators

13. 13
Banbury mixer
➢ Heavy duty two-armmixer
➢ 30 to 40 rpm
➢ Solids enter from top and discharge from bottom
➢ Applications:
▪ Compound rubber and plasticsolids
▪ Masticate crude rubber
▪ Make water dispersion and rubbersolution
➢ Shorter time and smallbatches
➢ Cooling is done by:
▪ Water spraying on walls
▪ Circulating through hollow agitatorshaft

14. Banbury Mixer

15. 15
Design of Blades
➢ Sigma blade:
➢ Used for general purposekneading
➢ Edges are serrated to give a shreddingaction
➢ S-type Double-naben (fish-tailblade):
➢ Effective with heavy plasticmaterials
➢ develop high shearforce
➢ Z-type Disperser blade:
➢ Heavier and develop highshearing 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 gummymaterials)
➢ 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 additionalshear
➢ 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 orboth
➢ Continuously mix, compound, and work thermoplastics, clays, and other
hard-to-mix materials.
➢ Heating jacket is provided.

22. Mixer Extruder

23. 23
➢ Smooth metal rolls at variable speeds
➢ For pastes & deformable solids to intenseshear
➢ 3 to 5 horizontal rolls in vertical stack
➢ Material moves from slower to fasterones
➢ Batch roll mills has two rolls set in horizontal plane and require long
mixing time and attention
➢ Used for dispersing solids in rubber and plasticmaterials
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

26. Muller Mixer

27. ➢ In a pugmill the mixing is done by blades or knives set in a helical pattern
on a horizontal shaft turning in an open trough or closed cylinder.
➢ Solids continuously enter one end of the mixing chamber and discharge
from the other.
➢ In the chamber, they are cut, mixed, and moved forward to be acted upon
by each succeeding blade
➢ Pugmills blend and homogenize clays, break up agglomerates in plastic
solids, and mix liquids with solids to form thick, heavy slurries.
➢ Sometimes they operate under vacuum to remove air from clay or other
materials.
➢ They are built with jackets for heating or cooling.
Muller Mixer
Pugmills

28. Pugmills

29. ➢ Single-shaft mills utilize an enclosed mixing chamber, open-trough double-
shaft mills are used where more rapid or more thorough mixing is required.
➢ The chamber of most enclosed mills is cylindrical, but in some it is
polygonal in cross section to prevent sticky solids from being carried
around with the shaft
Muller Mixer
Note