Definition of Homogenizer
Homogenizer is generally designed to mix and homogenize of solid particles in a liquid (or two non-solvent liquids) that make a suspension, emulsion or complete solution by dispersing solid particles into the liquid. The mechanical homogenizer consists of a spinning rotor and a stationary stator. This type of homogenizer is also called a high shear homogenizer, mixer-homogenizer or rotor-stator mixer. When the rotor blades rotate, drawing the materials (both solid and liquid) upwards from the bottom of the vessel and then returns them radially through the stator pores to the tank. In this process, the solid and liquid particles are crushed by high shear and a homogeneous mixture is obtained with uniform particle distribution. In other words, the high rotor speed (from 3000 to 20000 rpm) and the fine pores of stator cause the sample to be mechanically sheared into fine particles (smaller than 100 microns). The key effective parameters in the homogenization process are: sample size, volume and concentration of material, rotor rotation speed, operation time and viscosity of sample. Since mechanical homogenizer with rotor-stator mechanism can homogenize sample with low energy waste at short time compared to other mixing methods, it has received much attention in various industries. The rotor and stator are usually made of stainless steel (304 or 316). Mechanical homogenizer is used to homogenize samples from low volume (0.2 mL) to high volume (20 L).
Application of Homogenizer
Homogenizer is widely used in pharmaceutical industries (vaccines, drug synthesis, injectable suspensions, etc.), food industries (mayonnaise, cheese, milk, salad sauce, ice cream, etc.), cosmetic industries (shampoo, detergent, lotion, toothpaste, hair dye, cream, etc.), chemical industries and textile to make homogenous solutions, dyes and edible products. Homogenizer is commonly used to make stable emulsions with medium and low viscosity range (about 10000 cp). However, homogenizer with professional design can also homogenize concentrated materials (50000 cp).
How Homogenizer works
As mentioned earlier, mechanical homogenizer is designed based on the rotor-stator mechanism. Rotor is spinning part and stator is stationary part of homogenizer. During the homogenization process, the homogenizer enters the mixture (two insoluble components). The high rotation speed of rotor blades creates powerful suction which drawing materials upward. Then, centrifugal force drives materials into inner wall of stator where the shear force between rotor blades and stator wall cause crushing process. Subsequently, materials are forced to intense high speed hydraulic shear which causes exit of materials from stator pores that mixed in the main body. The materials expelled from the head are projected radially at high speed towards the sides of the mixing vessel. At the same time, fresh material is continually drawn upward maintaining the mixing cycle. The effect of the horizontal (radial) expulsion and suction into the head is to set up a circulation pattern that minimizes aeration caused by the disturbance of the liquid’s surface.
Homogenizer performance in 4 steps
Main equipment of Homogenizer
Stator: this equipment is a hollow cylinder with holes in its wall. Grinding and crushing of materials is the main task of stator. In fact, combination of stator and rotor and the friction that is created between empty spaces of them cause grinding and crushing. Different types of stator are used in various industries: slot (rectangle), spherical (fine grain), round (large circles), square and delta (bean-shaped). Slot stator is one of the most common types of stator that has suitable shear and rotation. Round and large rectangle pores are suitable for situations where high rotational speed is required and are often recommended when large solid pieces must be crushed into the mixture. On the other hand, fine pore stators are generally used in the preparation of emulsions. The Delta stator has also performed better than the others. The following figure shows the common types of stator.
Different kind of rotor and stator
Maximum shear is similar for different stator types, but the residence time within the mixing chamber varies. The following is a stator (delta type) which is designed by the Vandad machinery.
The stator which is designed in Vandad Machinery
Rotor: rotor is the spinning and rotating part of homogenizer. The rotor consists a number of blades. One of the important factors in designing a rotor is its distance from the stator body. The rotor has a high rotational speed, usually its linear speed varies from 10 to 50 m / s. The following is a rotor which is designed by the Vandad Chemical Industry team.
The rotor which is designed in Vandad Machinery
Main movable shaft: this shaft transfers rotation from motor to rotor. The end of shaft has two stairs. The bearing is in the first stair and the second stair connected to the coupling (and then to the motor). The beginning of the shaft (stator and rotor side) also has two stairs, the bearing is in the first stair and made of stainless steel (316). The second stair is connected to rotor and bolts.
Three retainer shafts: these three shafts hold and connect stator to motor. These shafts are crewed to the stator plate and then bolted to the top plate.
Shaft connection plate: a plate is mounted at the top of the system in order to connect three shafts as well as to hold the movable shaft.
Engine maintenance part: this part will vary depending on the engine type and the holes available for engine maintenance. One side of this part is connected to the motor and the other side in connected to the shaft connection plate. This part is important to maintain engine especially at high speeds.
Engine cover (Polyethylene part): this part is designed to protect the engine’s inner compartment from liquids, dust and also to maintain the engine’s position. It is diameter and length are determined based on the motor type. Holes are embedded on the body to allow fan’s air to pass.
Coupling: connects the output shaft of motor to shaft of homogenizer. At high speeds and in specific applications, coupling design requires specific technical knowledge.
Advantages of Homogenizer
- Low noise
- High efficiency
- Ability to homogenize high volume of materials
- Suitable for continuous industrial processes
- Suitable for materials with different viscosities
Design, manufacture and after sales service
With many years of valuable experience in manufacturing of industrial machinery and using its specialized engineering team, Vandad Chemical Industry Company has designed and manufactured rotor-stator homogenizer with state-of-the-art technology for use in various chemical, pharmaceutical, and health industries. The homogenizer is designed and manufactured using specific standards based on the feed and product properties. Vandad Machinery is capable of producing rotor-stator homogenizer in different dimensions for each requested capacity. Manufactured machines have up to 1 year repair warranty. Moreover, different points such as how to start, operation setting, how to shut down the system, maintenance , etc. will be given in a separate booklet (final book).
Please contact us for catalog and price list.