The science and skill behind a rapid mixer granulator

One of the important machines in a pharmaceutical factory is the rapid mixer granulator. Fine powder formation is very important when it comes to medicine as diligent care has to be taken while making them. An RMG machine is not merely a powder grinder but a complicated device which ensures the best results. Here is a simplified explanation of the science behind a rapid machine granulator.

First, we need to know the important parts that comprise of the machine. They may vary from brand to brand, but most typical high shear machine granulators comprise of these definite parts. Before that, we highlight the sequential process of the basic working of this machine.

1.     Mixing of dry materials at the high chopper and impeller speed for limited minutes.

2.     The Introduction of the liquid binder into the mixture, while both impeller and chopper are doing their job at low speed.

3.     Wet massing with both agitators operating at high speed.

Main Impeller and Drive: The impeller contains a dual HP TEFC motor that is coupled to a belt drive to a gearbox. The manufacturers intend the impeller to perform mixing at the bottom and at the center of the bowl, and this impeller is driven by the exclusive bearing housing. This housing enables inner washing and prevents powder leakage from entry at the bottom and makes gearbox durable.

Chopper: The chopper drive breaks the particle and chops them into granules. During wetting, it also breaks the knots and makes the even dischargeable product.

Discharge Port: This port is mounted horizontally into the bowl and has a vertical downward opening. Pneumatic cylinder operates the opening and handles the discharge.

Control Panel: The control panel is mounted on the platform and has switching, speed, and automaticity controls. There is a timer, indicator lights, controls for discharge opening or closing, ammeter/voltmeter for motors, air regulator and pressure gauge, air filter, and an optional PLC control panel.

Pneumatic System: This system is used for operating the discharge valve air purging of chopper drive and the impeller drive to avoid cross contamination. The system also contains air filter pressure gauge and other pipes and pneumatic fittings.

This is how the working behind a rapid mixer granulator pans out.

The machine is a mixing unit with a bottom entry agitator ad side mounted chopper for granulation.  It is used for dry blending, wet mixing, preparation of dough and granulation, i.e. cutting of the wet mass into small size granules. It works on the basic principle of agitation of the contents of the bowl at moderate speed and then running a specially profiled cutter blade at high speeds into the wet mass. Dry mixing takes about 3-5 minutes to mix the ingredients, wet mixing takes 5-10 minutes to make the wet mass of material while the granulation process takes 5-10 minutes to 0.5 mm to 1.5 mm sized granules. Mixing time consumed in processing depends upon the quantity and particle size of the ingredients.

Here are a few reasons why a high shear granulator is used more than any other machine:

§   Granulation process requires less binder solution.

§   Granulation is achieved within a short time.

§   Greater densification and production of less friable granules.

§   The granulator produces reproducible less friable granules with a uniform particle size distribution.

§   High-shear granulator minimizes the exposure of drug dust to workers due to reduced process dust generation.

§   Granulation endpoint is predictable while using high-shear granulator.

§   Requires short drying times.

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Created on Feb 27th 2020 05:02. Viewed 312 times.

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