WORKING
In Rapid mixer granulator Mixing, Densification and Agglomeration is achieved using Shear mixing(Breaking inter-molecular forces) and Compaction forces exerted by Impeller on the powder mass.
RMG consists of Mixing chamber, Impeller, Chopper, Discharge port, Filter assembly, Purging air and Solution inlet port.
Mixing Chambers in Rapid mixer granulator is of 3 types Conical shaped, Domed shape, and Circular shaped although the basic aim behind all the shapes is to eliminate the dead points and wall adhesioni.e.the powder may not adhere to wall from where it cannot detach leading to inefficient granulation as well as mixing.
Filter assembly is on the top of port in this vent air filter is placed which allows the purging air to leave the Mixing chamber and retains the granules inside.
Purging air air coming from gasket present below the impeller at an pressure of 5-6 kg and prevents the mixing of granules with lubrication of impeller thus preventing contamination.
MIXING BOWL AND COVER
S.S. quality bowl design in three sections i.e. Flat bottom cylindrical mid portion and conical top portion for efficient mixing operation & provided with counter balanced lid.
Lid provided with vents, view ports & charging openings.
Cylindrical large diameter shell with Flat bottom and conical top constructed form S.S. 316 quality sheet. Dome Type swing away Air tight cover with clamps – hinged type. Product Outlet having discharge chute with pneumatically operated Valve on side of the bottom.
IMPELLER THE SCIENCE BEHIND
The speed of Impeller should be high enough to cause Roping flow motion as slow speed causes Bumping motion of powder and leads to Inefficient mixing.
Bumping motion and Roping motion.
At higher speed of Impeller size of granules increases and if high speed is for longer time due to continuous collisions between the particles the size of granules will decrease.
The gap between base of mixing chamber is around 2.0 mm which is enough that the granules pass below the impeller blade without breaking.
MAIN IMPELLER & DRIVE
The main impeller consists of dual speed 750/1500 synchronous dual suitable HP N FLP motor, coupled through a belt drive to a worm reduction gearbox with chain coupling.
The impeller is designed to provide mixing at the bottom and at the center of the bowl and is driven through a specially designed bearing housing that facilities inside wash facility for quick change over and also prevents leakage of powder from bottom entry and leads to longer life of gear box RPM of main impeller is 75 & 150.
MIXING ARM
S.S. 316 quality. Three Blades made to triangular profile, welded construction fixed on a Hub. The complete assembly is connected to the drive shaft by dome shaped nut having wings for tightening. The Blade assembly is easily detachable.
Drive for the mixing arm comprises dual speed motor 750/1500 RPM, 415 Volt, 50Hz, 40/50 HP. Coupled to a Power Master gear unit through V Belt & Pulley. The Final RPM shall be 75/150.
CHOPPER THE SCIENCE BEHIND
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 .
SUPPORT COLUMNS
The chopper drive consists of dual suitable HP dual speed (1440/2800 synchronous speed) N FLP motor.
The motor shaft is of SS and the chopper has specially designed 4 blade SS impeller. The shaft is integral with the motor.
The assembly mounted horizontally into the bowl.
RAPID MIXER GRANULATOR
Binder should be added slowly not suddenly as sudden addition of binder leads to inefficient distribution of binder and may cause hardness variation in tablet.
END POINT
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 Optimization of batch.
CO - MILL
It has the online CO-Mill on the discharge port that reduces the oversized lumps. It results in a reduction of drying time by approximately 20%. As the lumps are small products, they can be uniformly dried at lower temperatures. Hence providing it a longer shelf life and eliminating casing & capping of tablets due to improper drying.