Analysis of ribbon blender, ploughshare mixer, conical screw mixer and paddle mixer

06-11-2014

Background:

With the development of industry, powder mixers are popularly used in different kind of industries such as food, animal feed, chemical, pharmaceutical, building material, dyestuff and fertilizer. So, we should choose the right mixer focusing on different industries’ demand and different mixing functions. Let’s see from industry. For example: food and pharmaceutical pay more attention on GMP or FDA standard; building material highly focuses on efficiency and wear resistance. If see from mixing functions, the mixers are widely used for mixing, coating, drying and reaction. Therefore, choosing the right mixer is very important for customer to realize their process well and get more benefit from mixer.
Nowadays, powder mixers can be classified following types: ribbon blender, plough shear mixer (or we can also use plow mixer), conical screw mixer (or we can also use Nauta Mixer), twin shafts paddle mixer and vertical ribbon mixer. Different mixer has its own advantage according to the mixed material. So, we make an analysis on above types of mixers to help customer choose the right mixer for their product.

Ribbon Blender:

Principle
Ribbon blender or ribbon mixer has U shape shell with double helical ribbon agitator. The outer ribbon makes material from two end sides to the middle and inner ribbon makes material from middle to two sides which shape a convectional status.

Advantage
1. Mild mixing which will not break the physical size of material
2. More loading factor (between 40%-70%, but generally speaking, 60% is maximum for heavy bulk density material)
3. Easy cleaning
4. Easy Maintenance
5. Low Power Energy

Applications
1. Dry powder mixing
2. Dry powder mixing + liquid spraying

Typical Processed Material
1. Milk powder
2. Baby food
3. Bakery Powder
4. Nutritions
5. Plastic
6. Resins
7. Detergent Powder
8. Animal Feed

Plough Shear Mixer:

Principle
Plough Shear Mixer is widely used for different kinds of applications such as mixing, coating, drying and reaction with very high homogeneity. Plough Shear Mixer has different name in different area. In America, people call it as plow mixer, In Europe, people like to call Plough Shear Mixer or Ploughshare mixer. It has a cylindrical shell with plough shovel welded or bolted on arms and the shaft runs at high speed to effect a fluidizing action. The plough shovel lifts the material upward, and the material settles in a pattern. Whirling, three-dimensional product movement makes output material with very high homogeneity within short mixing time.

Advantage
1. Fast mixing with chopper which can break the caking of material
2. High Homogeneity
3. Multiple Functions like mixing, coating, drying and reaction
4. Short mixing time
5. Flexible design according to processed material
6. Easy cleaning
7. Easy maintenance

Applications
3. Dry powder mixing
4. Dry powder mixing + liquid spraying
5. Paste mixing
6. Wet mixing
7. Liquid coating of powders and granules
8. Vacuum drying

Typical Processed Material
1. Food Flavoring
2. Sugar
3. Starch
4. Soap
5. Chemicals
6. Pharmaceuticals
7. Ceramics
8. Agrochemicals
9. Veterinary
10. Adhesives
11. Brake linings
12. Confectionery products
13. Detergents
14. Waste treatment
15. Fiber Glass
16. Rubber
17. Building Material

Conical Screw Mixer:

Principle
Conical Screw Mixer can also be called Nauta Mixer. It consists of drive part, cylinder and screw agitator inside. The screw will lift the material up by fast speed and removes material away from the wall and deflects it into the centre of the vessel. Repeat rotation and revolution of the screw and form shearing, convection and diffusing inside the tank.

Advantage
1. Low shearing
2. Mild Mixing
3. Clean Discharge
4. Big Capacity
5. Low Energy Consumption

Application
1. Free flowing powder mixing
2. Granulation
3. Coating
4. Slurry Mixing

Typical Processed Material
1. Food Powder
2. Engineered plastic resins
3. Pesticides and herbicides
4. Pharmaceuticals
5. Fertilizers
6. Plastic powders
7. Rare Earth
8. Polymers
9. Chemicals
10. Talcum powders

Twin Shaft Paddle Mixer

Principle
Twin Shaft Paddle Mixer consists of two shafts and two semicircle vessel. The material will be lifted up by overlapping paddle and make material in a non gravity action which will have a perfect mixing homogeneity result.

Advantage
1. Fastest mixing time
2. High homogeneity
3. Low shear forces
4. Quick discharge time and low residues

Application
1. Dry powder with small liquid spraying
2. Short fibers
3. Granulation

Application
1. Flour
2. Flavoring
3. Animal Feed
4. Dry Mortar
5. Cement
6. Pre-mixed Cement
7. Lime
8. Flooring Material
9. Gypsum
10. Road Lining Material
11. Wall Plaster
12. Glass Fiber
13. Clay
14. Sand
15. Pumice

Analysis Conclusion
Through above introduction of different types mixers’ principle, we can get conclusion as following:
 Mixing time:
Twin shafts paddle mixer and plough shear mixer are both have fast mixing time between 1-3 mins for free flowing powder material. Conical screw mixer has the longest mixing time around 8 mins compared with paddle mixer and plough shear mixer.
 Mixing homogeneity:
According to the mixing principle and customer using experience, twin shafts paddle mixer and plough shear mixer are both have high mixing homogeneity in short mixing time because the tip speed of these two mixers are faster than ribbon and conical mixer. Although the adding percentage is below 1% or even smaller, twin shaft paddle mixer and plough shear mixer can also have a good result.
 Mixing Shearing Force:
Ribbon blender and conical screw mixer are both mildly mix which will not break the physical size of the material.
 Discharge
Seeing from structure of these mixers, conical screw mixer has the smallest dead space and clean discharge because the discharge valve is at the bottom of vessel. Twin shaft paddles mixer could be designed as Bombay discharge door which can make discharge door on vessel as big as enough.
 Multiple Function
More and more customers want mixer not only for mixing, but also for drying, coating and reaction functions. So, there will be vacuum, pressure for the mixer. According to the structure of different mixers, plough shear mixer is the most suitable to meet vacuum, high pressure.

According to process and material to be mixed, we can list some typical processed material:

 Dry Mortar (Building Material)
It need wear resistance agitator such as Hardox steel, Alloy steel or doing some special wear resistant treatment for mixing agitator.
Suitable Mixer: Plough Shear Mixer, Twin Shafts Paddle Mixer

 Food
Frequent cleaning and GMP requirement is normally used in mixer. So, the mixer shall to be designed as easy clean and round smooth for mixing agitator.
Suitable Mixer: Ribbon Blender, Plough Shear Mixer

 Dyestuff
It need big capacity mixer to fulfill large capacity. Easy discharge is also very important because the dyes is a bit sticky.
Suitable Mixer: Conical Screw Mixer

 Plastics and Polymers
According to the physical feature of this kind material, the size is easily broken by high speed shear. So, it needs relative mild speed in order to keep the original size of the product.
Suitable Mixer: Ribbon Mixer, Conical Screw Mixer

 Fertilizer
For the ingredient in fertilizer, it has some percentage of polyurea which is easy to be melted if meet high temperature. Therefore, short mixing time and low temperature is necessary for choosing mixer.
Suitable Mixer: Twin Shafts Paddle Mixer

Powder mixer is playing an important role in every industry’s process. Choosing right mixer can help customer get ideal product for more economic benefit. We do not just mixing your material, but lifting customer’s business.