Agitator bead mill

Types of Agitator Bead Mills

An agitator bead mill is a kind of grinding machine specifically used for wet grinding. The grinding process is performed by the grinding media that are held in suspension by the liquid for the specific product being processed. Apart from the common function of grinding,, the agitator bead mill also homogenizes the product being processed.

The main functioning parts of an agitator mill consist of a chamber to hold the slurry, a separator system to prevent the grinding media from exiting the chamber, and the motor that drives the agitator to disperse the material and the grinding media throughout the chamber. The separator system in an agitator bead mill is more sophisticated than in other types of wet mills. This allows the bead agitator mill to grind objects of micro and nano sizes.

There are two main categories into which the different types of agitator bead mills can be classified: their feeder and discharge design, which are attributed to how the product enters and exits the grinding chamber; and their grinding media separation mechanism. The following sections will elaborate on the different types of agitator bead mills based on these classifications.

• Permalon Membrane Feeder Mills: As the name suggests, the Permalon membrane feeder mills use a membrane as a barrier to separate the product that needs to be ground from the grinding media. This membrane allows the unground product to pass through while preventing the grinding media from passing through. The membrane is also used to feed the product into the grinding chamber. This type of mill is seen in smaller-scale iterations.
• Pressure Drop Mills: Pressure drop mills work on the same principle as membrane feeder mills. The feed product is pushed into the grinding chamber. However, in pressure drop mills, the external force separating the ground product from the grinding media is the pressure drop caused by the recirculation pump. These types of agitator mills are better suited for processing smaller quantities of material.
• Slot Separator Agitator Bead Mills: The slot separator bead mill uses a slot to separate the ground product from the unground product. The slot mils separator works on the same principle as the pressure drop or membrane separator. However, it is more suited for larger quantities of products. The slot also allows for more throughput than other types of separators.

Other types of agitator bead mills are primarily based on the separators used between the ground and unground product. The high-performance classifying agitator bead mill uses a classifying wheel to separate the ground product from the unground product. Classifying wheels have various advantages, such as fine material being discharged at a higher throughput and reduced energy use as the separator requires less energy to run than others.

The apart from the separators, other bead agitator mills can be distinguished based on their design and grinding method. For example, the annular chamber bead mill uses a circular chamber to grind the product. This design allows for high-efficiency milling and easy cleanout after use. Another example is the disc agitator bead mill. Disc agitator bead mills use discs as their agitators. The discs are mounted on a shaft, which then shears the product apart. These types of agitator mills are more suited for larger products that need to be processed at a greater quantity.

Choosing the right type of agitator bead mill depends on the specific needs of the industry and the product being processed. When choosing, buyers should consider factors such as batch size, desired particle size, separation efficiency, cleaning requirements, and specific capacity limitations. A wrong choice may lead to increased energy costs, a longer processing time, and reduced end product quality.

Specification and Maintenance

The specifications for the agitator bead mill can vary depending on the model, make, and intended use. These are some typical specifications to consider when buying an agitator bead mill.

• Rotor Diameter

  The rotor diameter refers to the bead mill's stirring component's circular cross-section. Different rotor diameters will affect the processing volume, shear rates, and temperature that the agitator will produce on the material being processed. Larger rotor diameters work faster, process larger volumes, and create more shear. Smaller rotor diameters take up less space, process smaller volumes, and produce less shear. The standard rotor diameters are 50, 55, 60, and 75 mm.

• Installed Power

  Installed Power is the maximum input power that the agitator bead mill can receive. It is constant and determines the bead mill's processing capabilities. Larger bead mills have more installed power. For example, 25 kW, 30 kW, and 37 kW.

• Wet Grinding Volume

  Wet grinding volume is the maximum capacity of the mill to process material in liters or gallons. It shows the amount of product that can get ground in a single pass. The wet grinding volume is a critical specification for commercial mills that produce high quantities of ground material. Smaller agitator bead mills may have a capacity of 75 liters. Larger bead mills designed for immense volumes have a wet grinding capacity of 750 liters or more.

• Materials of Construction

  An agitator bead mill must be resistant to wear and corrosion from materials. So, many mills will have parts made of special wear-proof steel or even ceramic. The choice of material can affect the quality and color of the product being processed-mostly used materials include stainless steel, carbon steel, and hardened alloys.

Maintenance

Proper maintenance and cleaning of an agitator bead mill extend its life and maximize performance. Few maintenance tips and things to remember during cleaning.

• The mill should be installed and operating in a well-ventilated area.
• Always put on safety eyewear and headgear before starting cleaning the mill.
• The agitator bead mill has to be stopped and cooled down before beginning any cleaning.
• Make sure to clear the area around and under the bead mill before cleaning.
• For dry bead mills, vacuum or blow compressed air inside the chamber to remove bead and product debris. Then, begin washing the external surfaces.
• For wet bead mills, use a non-conducted product or water with a very low conductivity to flush out the system. Add the cleaning solution into the feed tank. Run the bead mill in the cleaning circulation mode worth the solution in the grinding zone.

Scenarios

The applications of an agitator bead mill are numerous and varied. They can be found in many industries and different sectors of the world economy.

• Food Industry: In the food and beverage business, products must have a fine texture, great taste, and enough shelf life to please consumers. This is the reason why an agitator bead mill is used to grind down food and beverage items like coffee, juice, milk, tea, edible oils, flower extracts, and sauces to very fine particle sizes. It can also be used to reduce the size of nutritional supplements and food additives to a micro or nano scale so that they stay mixed and are easily digested by the body.
• Paint and Coatings Industry: In the paints and coatings sector, many dispersive and emulsifying liquid products are sold to consumers and industrial buyers. An agitator bead mill is used to break down pigment particles to make paint that applies easily and provides effective coverage. The coating industry also uses bead mill machines to reduce product particles to improve surface coverage, protection qualities, and durability.
• Chemical Industry: In chemicals, agrochemicals, and polymer production, tasks require the efficient processing of complex fluids and solids. A horizontal agitator bead mill machine is well-suited for this application, and it is extensively used to produce fine emulsions, dispersions, and suspensions that meet stringent quality and regulatory requirements. For example, pesticide formulations must be well-engineered at the micro and nano levels, and this can only be done using a chemical wet bead mill machine. Other chemical product examples that use agitator bead mills to be produced are inks, surfactants, and resin emulsions.
• Pregnancy Tests and Other Medical Industries: When chemicals are put together to produce liquid tests that can indicate what a woman or person has in his or her body, they need to be very fine and at a ready-to-use, easy-to-read level. This is the reason why beads agitator mills are used in the medical testing instrument industry. Medical testing machines, like DNA tests and pregnancy test kits, require a very fine chemical solution to be produced to run effective tests. Other medical machine examples include vaccines and drug delivery systems.
• Cosmetics Industry: Cosmetics need to be of uniform consistency and finely milled. The cosmetics industry uses an agitator bead mill to produce its makeup products like creams, foundations, sunscreens, tinted moisturizers, colored ointments, and facial serums and oils, to name just a few. The makeup industry is an extensive one with millions of products, and they all need to be finely milled before they can be put into a bottle or jar for human consumption.

How to choose an agitator bead mill

When choosing an agitator bead mill, several factors and features must be considered to ensure the selected mill meets specific processing needs.

• Material compatibility

  The mill must be made of materials that are compatible with the product being processed. The choice of materials for the mill's construction, such as the grinding chamber, separator, and beads, can affect the quality of the final product and the longevity of the mill.

• Size and capacity

  The size and capacity of the agitator bead mill should be considered based on the required grinding volume. This is important to meet the production needs without incurring excessive costs or leading to inefficient processing.

• Grinding method

  Different agitator bead mills employ diverse grinding methods, such as wet grinding or dispersion. The preferred method should be selected based on the material's characteristics and the desired final product.

• Cooling system

  Some mills offer cooling systems that help regulate the temperature during the milling process. This is important when working with materials that are sensitive to heat or when maintaining a specific temperature is crucial for achieving the desired properties in the final product.

• Automation and control

  Automation and control features in an agitator bead mill can improve efficiency, reduce labor costs, and enhance product consistency. The level of automated operation and control should be considered based on production requirements and desired operator input during the milling process.

Q&A

Q: How does the agitator bead mill work?

A: This type of mill works by using the agitator to expose the particles to friction and shear forces arising from the beads colliding with each other. As a result of these forces, the particles are broken down to the desired size.

Q: What are the main components of the agitator bead mill?

A: The main components of an agitator bead mill include the grinding chamber, the pin agitator, outlet, inlet, and separator.

Q: What are the differences between the horizontal and vertical agitator bead mill?

A: The horizontal bead mill positions the mill's axis of rotation horizontally. It has a compact design that is easy to integrate into process lines. Also, it offers high efficiency for fine grinding. On the other hand, the vertical bead mill features an upright cylindrical chamber. This mill exposes the beads to the particle for a long time, hence achieving a high degree of particle size reduction.

Q: How is the safety of the users ensured in the agitator bead mills?

A: The bead mills are usually equipped with various safety features such as pressure relief valves, interlocks, and sensors to ensure the operator's safety.