Conical Mill: The Ultimate FAQ Guide

If you’re looking for any information about conical mill, you will find it right here.

This guide covers everything you need to know about conical mills – from features, parts, working principle, and uses, amongst others.

So keep reading to learn more.

What Is A Conical Mill?

A conical mill is also known as a cone screen mill.

It is a unique machine you can use for size reduction in pharmaceutical industries, food processing, or other industries.

Besides, it has a knife/rotary impeller fitted chamber that is cone-shaped, hence the name.

It reduces the sizes of large products, which can be hard or medium, into small, soft pieces.

Generally, it plays an integral role in the material processing industry, reducing large product particles to smaller particles.

The Inside View Of A Conical MIll

The inside view of A Conicall MIll

What Are The Applications Of Conical Mills?

You can apply the conical mill in the following processes:-

  1. Reduction of the size of dry materials in products; this will increase the material’s surface area and, in turn, increase its solubility rate.
  2. Deagglomeration; here, you can use the conical mill to break apart powder or crystals without further disintegration.
  3. Granulation; this process involves forming grains from powdery or solid matter, later packed as granules and used as dosage. The conical mill provides spectacular results.
    You can divide the process into two, i.e., dry granulation and wet granulation—the difference between the two arises from whether or not they require liquids during processing.
  4. Sizing of wet materials; using the conical mill in this application allows the materials to dry faster due to the large surface area.
  5. You can use it to retrieve powder from tablets that do not meet the required standards for reuse in the processing industry.
  6. Dumping through shredding of the oversized products to the required standard size.

A Sanitary Cone Mill For Moist , Sticky And Fragile Materials

A Sanitary Cone Mill For Moist , Sticky And  Fragile Materials

What Are The Types Of Conical Mills Available?

Some of the available options include;

Tabletop Laboratory Conical Mill

This type of conical mill has a stand that you can use to place it on a surface. It comes as a self-contained portable unit that is essential for size reduction mixing and granulating. They are constructed from durable, high-quality stainless steel.

A Tabletop Conical Mill

A TableTop Conical Mill

Under Driven Conical Mill

These conical mills have an increased throughput with 50 % more capacity compared to other types of conical mills. They use centrifugal force for sifting and milling. Under driven conical Mills come as adaptable and flexible designs with interchangeable rotary shifters.

Under Driven Conical Mill

An Under Driven Conical Mill

Comminuting Conical Mill

They are designed for dry and wet granulation of pharmaceutical materials. They also cater for their dispersal. The machines have the following parts: heavy-duty motor, sieve, beater assembly, processing chamber, throat hopper and hopper, among other parts.

Communiting Conical Mill

Communiting Mill

Oscillating Granulator Conical Mill

It is suited to meet the needs of dry granulation of pharmaceutical materials. It is easy to roughly guess the granulator to this type of conical mill from the name. The main part of the conical mill is oscillating – “turning around” or “revolving” to make the material milling process easy.

Oscillating Granulator

An Oscillating Granulator

What Are The Parts Of Conical Mills?

The conical mills have the following parts:-

  1. Rotary knife/impeller:- This part has three or two blades because it is the only rotating component of the conical mill. They are available in two types, i.e., round impellers and square bar impellers.
  2. The feeding hopper:- This part is cone-shaped and plays the vital role of containing raw powder materials during the feeding stage. However, it may not exist at the IBC/bin to the conical mill connection point.
  3. Mesh screen:- This part is a screen or sheet with perforated holes. These holes can be of different sizes and shapes, depending on your process requirements.
  4. Drive system:- This part provides the power that enables the impeller to rotate. There are different options for this part, i.e., gearbox drive, belt drive and direct drive. It can be remote, under, or top.
  5. Base and frame support:- This part anchors the conical mill to the tabletop, floor, or wherever you mount it. It can be a fixed base frame or movable chassis, depending on your preferences.
  6. Receptacle:- This part holds the processed powder grains after they pass through the mesh screen. If you would like automatic conveying, you could connect vacuum transfer equipment to the receptacle.
  7. Seals:- These parts are made from PTFE materials or silicone.

Dissection Of Parts Of A Conical Mill

Dissection of Parts Of A  Conical Mill

How Do Conical Mills Work?

It is quite easy to understand how conical mills work. The steps involved in the milling process occur chronologically as follows:-

  1. Step one is feeding the materials through an infeed chute into the conical mill chamber. You can do this easily using gravity. This is because the IBC drum/bin is inverted and interlocked onto the surface of the conical mill.
  2. The next step is the breaking down of powder particles. The powder comes into contact with the rotating knife/impeller, where it undergoes attrition and shearing. Afterwards, it is flung onto the mesh screen.
  3. Step three. At this stage, the desired grain sizes will pass through the perforated mesh screen.
  4. The finished particles are then collected in a receptacle component.

Note:-

If you require smaller granules, you should increase the speed of the rotating knife/impeller. This will flatten the particle’s angle of approach to the surface of the mesh screen.

What Factors Affect The Efficiency Of Conical Mills?

  1. Lubrication:- Parts such as blades and granulators slow down the conical mill’s speed if not properly oiled. Not oiling frequently may cause the formation of rust. Additionally, lubrication influences friction rates, thus influencing the efficiency of the conical mill.
  2. The mesh perforations:- The sieve pores affect the end product’s granularity. Hence, the size of the holes will affect the efficiency of the conical mill.
  3. The temperature of operation:- You should not operate the conical mill under high heat conditions, which will alter product quality. The milling process yields heat. Try to maintain this yield at a minimal to none level. A lot of time will be wasted in cooling off the conical mills, thus reduced efficiency.

What Are The Advantages Of Conical Mills?

Conical mills have very many inherent advantages over other equipment used for size reduction. Such advantages include:-

  • You can quickly and easily replace the impeller and sieves if the need arises.
  • The residual powder will not build up because of the mill’s conical shape.
  • Conical mills generate very little heat and also have low noise levels.
  • They are versatile, meaning you can use them in a variety of industrial size-reduction applications.
  • Conical mills are capable of gentle milling. This result in low fine fractions.
  • They are easy to clean and hygienic.
  • The particles they produce have uniform properties.
  • They are less labour intensive as they do not require full-time human oversight.

Fine Uniform Partcicles Produced From A Conical Mill

Fine Uniform Particles Produced  From A Conical Mill

How Do You Maintain Conical Mills?

  1. The conical mills are quite easy to maintain. The detachable mill head, which is an optional feature, makes them easy to clean.
  2. Conduct regular temperature monitoring tests to ensure that the conical mills are still operational.
  3. Clean the mesh screen regularly to remove any debris that could be stuck in the holes.
  4. Finally, lubricate the conical mill frequently. Parts such as blades and granulators slow down the conical mill’s speed if not properly oiled. Not oiling frequently may cause the formation of rust. Additionally, lubrication influences friction rates, thus influencing the efficiency of the conical mill.

Which Features Should You Consider When Choosing Conical Mills?

Deciding that conical milling is the right type of methodology for your business will depend on:-

  1. The material is being processed.
  2. The target particle size and PSD.
  3. The production capacity needed.

Conical milling is particularly suited to achieving particle ranges from 4750 microns to 250 microns with tight PSDs.

Thus, it would be best to choose the right screen hole type and size, impeller and tip speed that conform to those requirements.

With the proper model selection, they can deliver very high capacities for such a small footprint. Moreover, due to the low residence time in the mill, they are suitable for many heat-sensitive products.

Apart From Conical Mills, Which Other Material Size Reduction Equipment Can You Recommend?

We recommend the following equipment for your material size reduction needs:-

  1. Hammermill:- This equipment applies an impact action principle in its operation. You can use it in almost all drugs but not on abrasive materials.
  2. Tumbling mill, also known as ball mill, operates based on the contact between powder and moving balls enclosed in a hollow cylinder. You can use it for processes that involve milling brittle materials.
  3. Ultrafine grinder, fluid energy mill or jet mills:- These mills employ the impact and attrition principle to reduce material sizes efficiently. You can use them for moderately hard and friable and non-sticky materials.
  4. Rotary cutter mill:- This mill uses the principle of cutting with sharp knives. It is suitable for animal and vegetable drugs and non-friable materials.

Other types are- Colloid mill, End and Edge runner mills.

A Hammer Mill For Small And Medium Sized Feed

A Hammer Mill For Small And Medium Sized Feed

Rotary Cutter Mill

Rotary Cutter MIll

What Parameters Influence Material Size Reduction By The Conical Mill?

  • The hardness of the material being processed. The harder the material, the more difficult is the size reduction.
  • Toughness and fibrous drugs. You should lower the temperature when reducing these materials. It is beneficial since it reduces the decomposition of thermolabile materials. Besides, it also does away with explosion, oxidation, and loss of volatile materials.
  • Sticky materials make it difficult for size reduction as they stick on the surface; this can. You can, however, solve this by drying or adding inert materials.
  • Slippery materials act as lubricants that also increase the efficiency of a conical mill machine.
  • Moisture content influences the hardness, stickiness, and roughness of a material.
  • The melting point of the material.
  • Size of starting material.
  • Quantity of material to be reduced.
  • The feed size to product size ratio.

How Do You Approximate The Conical Mill Energy Requirements?

You can use the following laws to estimate the energy you will need for size reduction:

  1. Rittinger law:- The amount of energy you will need for material reduction in cone mill is proportional to the surface subjected to shear forces. This law is more applicable to a fine powder.
  2. Kick’s law:- Here, the useful energy you will require for reducing material sizes is proportional to the logarithm in the ratio between initial and final diameter.
  3. Bond’s law:- Stipulates that useful work to reduce particle sizes is directly proportional to the new surface area.
    But also, the length of the crack is proportional to the square root of the new surface area produced. It therefore implies, the amount of useful energy will be inversely proportional to the product diameter square root minus the diameter of the feed.

What Do The Terms Vacuum Transfer And Gravity Feeding Mean With Regard To Conical Mills?

In the conical mill, vacuum transfer is an automated way of receiving materials directly from the hopper.

In gravity feeding, the conical mill depends on the gravitational force to material from the hopper.

Which Industries Use Conical Mills?

The applications of conical mills vary depending on which industry you use them in. One of its most common application areas is the food sector in general, specifically, the agrifood sector.

In this sector, the conical mills enable product milling, screening and washing, i.e., their deagglomeration capabilities.

They are also applicable in the pharmaceutical industry. Conical mills are widely regarded as the most efficient in sorting different particles in this industry.

The waste management industry also uses conical mills.

However, the specific type of mills will vary depending upon the waste type and its consistency.

In a nutshell, you can use conical mills in waste management, fine chemistry, cosmetics, pharmaceutical, and food industries.

What Is The Difference Between Overdriven Conical Mills And Under-driven Conical Mills?

Once you have decided on a conical mill for your process, you choose between under-driven and over-driven mills.

Both will have advantages in different applications, so it is essential to know the process and material specifics before deciding.

Here’s a brief guide that highlights the critical differences between the under-driven and over-driven conical mills.

Under-Driven Conical Mill

Spacer-less design with the pre-set optimized gap for milling. Spacers are time-consuming to set up and heighten the risk of operator error in setting the gap correctly. The spacer-less design eliminates these issues.

In-line feed and discharge for higher capacity milling.

As the inlet is in line with the outlet on the milling chamber, it is better for in-line processing (e.g., container to container milling) and easier system integration due to the minimal stack-up height.

Hygienic, easy-clean design. Detachable mill head allows the chamber to be removed from the machine for easier cleaning.

Over-Driven Conical Mill

Perfect for heat-sensitive materials. An over-driven conical mill uses a belt-driven gearbox that runs cooler than the gear-driven alternative.

This means that the machine can run cooler and is, therefore, better suited for heat-sensitive materials.

Robust design for more rugged applications. The belt-driven design is generally more robust and is suited to tougher materials and plant-like materials.

Ability to change the gap between the screen and impeller. The over-driven conical mill uses spacers to set the gap, which allows the gap to be altered depending on the processed material.

Low noise for a better working environment.

Another advantage of this design is the lower noise created due to the belt-driven operation compared to mechanical gears.

How Do Conical Mills Incorporate Sifting And Material Milling Technologies?

They do this through a process known as deagglomeration. Here, materials are broken down into powder or crystals. They are then passed through a screen where only fine particles pass through.

What Types Of Sieves Are Available For Conical Mills?

With conical mills, you have a wide range of sieve types to choose from. The variations in these sieve types arise from the size and shape of the perforations. These types are:-

Round Hole Conical Mill Sieves:-

They are best suited for processes that involve size reduction of free-flowing materials, e.g., powders and granules. They are available in diameters ranging between Ø0.5-Ø3.

Square Hole Conical Mill Sieves:-

These are best suited for processes that involve deagglomeration and de-lumping of wet masses. This is because they produce coarse products.

They are available in dimensions ranging between 3*3-10*10.

Grater Hole Conical Mill Sieves:-

These sieves are quite easy to distinguish from the other types. The holes on these sieves have sharp cutting edges because they are raised. They are best suited for breaking hard substances down. For example, you can use them to break down tough seeds or sweets in the food industry.

How Much Do Conical Mills Cost?

Conical mills come at a reasonable price point ranging between 40 to 1000 dollars. The price is competitive and provides the highest value for your buck. Our conical mills will provide your process with the highest possible quality while coming at a reasonable cost.

At SaintyCo, we offer a range of conical mills, depending on your unique requirements and specifications.

You can also learn more from Fritz/Cone Mill, Conic Mill and SaintyCo cone mills.

For any questions or inquiry on conical mills – contact us now.

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