About RMG- Rapid Mixer Granulator - Part - 1/4

About Rapid Mixer Granulator (RMG)

Rapid Mixer Granulator are also known as the High Shear Mixer Granulator use for  dry mixing & wet granulation in pharmaceutical Industry for mix the pharmaceutical ingredients and make the uniform wet mass granules/mixing or dry mixing. As the name suggests, this machine performs two operations - Mixing and Granulating.

 

Granulation is an important process in tablet manufacturing. As a result of the granulation process, the particles stick together firmly by addition of binder (paste or solution ) which helps in increasing the particle size. High shear granulation machine efficiently executes the process of fast dry & wet mixing, and granulating of the powder.

 

RMG UTILIZE FOR TWO TYPE GRANULATION PROCESS

1. DRY GRANULATION PROCESS

The dry granulation process is used for uniform mixing without addition of any binder. It is most suitable for the materials that are moisture-sensitive, heat-sensitive or do not compress well due moisture issue.

 

2. WET GRANULATION PROCESS

Wet granulation is the process of adding the binder ( paste or solution)  to dry powders, which involves the massing of dry powder particles with the help of granulating fluid/binder. The wet granulator is used for the production of wet granules. The complexity of the wet granulation process depends on the characteristics of powder and the equipment.

 

Rapid Mixer Granulator primarily used for the manufacturing of tablets, Capsule filling powder manufacturing process which requires homogenous mixing, controlled granule size, and at the same time assuring a great reduction in processing time and gives uniform mixing of all ingredients.

Components & Process parts of RMG:

 

Here mention Components & Process parts of RMG not limited. It’s varying as per manufacturer of machine.

• RMG consists of different Components like:

1. Mixing chamber
2. Impeller
3. Chopper
4. Binder Inlet port
5. End Point
6. Top Lid
7. Discharge point
8. Purging air
9. Filter Assembly
10. Co-mill
11. CIP (Clean-in-Place) / WIP (Wash-in-Place) System
12. Control panel like HMI, IPC or PLC Programmable Logic Controller (PLC)

• Other Information about RMG:

1. PRINCIPLE OF RAPID MIXER GRANULATOR
2. General Process in RMG
3. Calculate For working capacity of the Rapid mixture granulator?
4. Process variable of RMG:
5. Advantage:
6. Disadvantage:
7. Safety Features

 

Components:

1. Mixing chamber

Most of the Rapid Mixer Granulator consists of a mixing bowl, a three-bladed impeller, and an auxiliary chopper. The mixing bowl can be jacketed for heating or cooling the contents in the bowl, by circulating hot or cool liquid or steam through the jacket as per product requirement and non jacket mixing type chamber widely used in pharmaceutical industry.

 

There are three types of mixing chambers based on their design used in pharma industry.

Mixing chamber Shape

Conical shape

Dome shape

Circular shape

 

The basic aim behind all the shapes is to eliminate the dead points and wall adhesion i.e. the powder may not adhere to wall from where it cannot detach leading to inefficient granulation as well as mixing. Hence the shape of mixing chamber has big effect on Product binding process.

 

2. Impeller:

The impeller is designed at bottom of the flat mixing chamber. An impeller is employed to mix the dry powder and spread the granulating fluid. The impeller of the rapid mixer granulator normally rotates at a speed ranging from (Slow- 75 RPM to fast 150 RPM). The impeller mixes the dry powder uniformly and prepares wet mass after the addition of the binder. It consists of large blades responsible for mix & for lifting the materials.

The mixing is achieved by paddle type impeller blades spinning close to bottom of the mixing bowl. The impeller blades are angled in a way that sets the entire mixture in a whirling - rising - tumbling motion ensuring a quick and even distribution of all dry components which leads to an even wetting of every granule.

The speed of Impeller should be high enough to cause material will in Roping flow motion as slow speed result material get Bumping motion of powder and leads to Inefficient mixing.

 

A- Bumping motion

At lower speed (Bumping motion) of impeller, continue the resulted granules have no uniform mixing with binder or paste which may result failure of product.

 

B- Roping motion

At higher speed of Impeller (Roping motion), due to roping motion size of granules increases and if high speed is for longer time collisions between the particles the size of granules will decrease.

 

The gap between base of mixing chamber and impeller is around 2.0 mm which is enough that the granules pass below the impeller blade without breaking.

 

3. CHOPPER

 

Copper fixed at side mounted bottom side of mixing chamber. Chopper has very sharp small blades which are specially designed to cut the wet lumps of material into very small piece which are then mixed by impellers and lead uniform wet granules or dry mix material.

The primary function of chopper is to cuts the lumps into smaller fragments those are mixed equally by impeller and aids the bowl or sprayed onto the powder to achieve a more homogeneous liquid distribution.

The use of chopper should not be done always as we know the chopper will break the granules.

Firstly look weather active is free flowing or cohesive, weather it lumps or not .Chopper should be used if active is cohesive or forms lumps at the minimum speed after solution addition.

Chopper used for break/cuts the large lumps formed by impeller in small granules for make uniform granules which occur  due to Binder (Paste or Solution) addition or during Kneading of wet mass till uniform granules.

RPM of Chopper (Slow 1440 to Fast 2880) use for product as per BMR instruction.

The process of convert wet mass into granules is called Kneading.

 

4. Binder inlet port for Binder (Paste or Solution) addition

 

Binder (Paste or Solution) should be added slowly not suddenly though Binder inlet port available on top of lid of RMG , as sudden addition of binder leads to inefficient distribution of binder and may cause hardness variation in tablet. It’s also leads to variation of drying, during drying process in FBD/FBE/FBP which result in uneven LOD (Loss on Drying) of final product.

For best result of granules, Binder addition should do by peristaltic pumps. So prior do validations of Peristaltic pump how much binder will go in one minute.

 

5. END POINT

 

A- For Dry Mixing:  Its Time base process only. In this process Fix TIME and RPM for Impeller and chopper available.

B- For Wet Mixing: is Ampere load base process mostly.

Ampere load on Impeller and Chopper I.E the current which is used by Impeller and chopper motor to rotate when granules are formed.

Ampere load is high in beginning when granulation starts as motors need more power and decreases as end point is reached.

End point could also be determined by ensuring the Vortex formation generally done by Research and Development personnel during Trial or Validation (3-batch) batches.

Take wet granules in hand and close the fist then open and break it throughout thumb, called a banana breaking method.

Ampere load mentions as per BMR when achieved stop the machine and record it from PLC or printout. 

As material get dense or bind more and more so it's increased hence vaildation require for each process to avoid failure of batch.

Click here for Next Contents: 

• About RMG- Rapid Mixer Granulator - Part - 2/4
• About RMG- Rapid Mixer Granulator - Part - 3/4
• About RMG- Rapid Mixer Granulator - Part - 4/4

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