Advantage and disadvantage of common granulation machine II
Writer： admin Time：2020-03-19 15:00 Browse：℃
High shear granulation consists of mixing (in special situations, some materials should be premixed) and granulation. Adhesive is still sprayed downwards. The liquid will wet medicine surface and generate adhesion force in powders. Then forced by liquid bridge and external mechanical force, powders agglomerate and form granules of certain shape and size. Some common problems and disadvantages of high shear granulation include:
1.Severe blocking of material, i.e. over granulation
1)Over granulation occurs when adhesive is fed too quickly or too much or granulation time is too long. Therefore, conditions in granulation should be controlled to avoid over granulation.
2)Some solutions to avoid over granulation are: controlling granulation time, checking current and checking torque. But these methods are not applicable for all materials. Therefore, prescription should be tested for its tolerance so that it can be used in practical production.
2.Loose granules and too much fine powders
1)High-content ethanol in adhesive will make granules loose.
2)Small dosage of adhesive or short granulation time will also influence granulation. Some materials don’t granulate, so more fine powders remain.
3)Inappropriate adhesive is used so that solid bridge cannot form in powders. It is suggested to use adhesive of stronger viscosity.
3.Some large wet granules and some powders
1)Mixing speed and rotating speed of granulating impeller is too low to distribute adhesive quickly.
2)Some materials are soluble in adhesive. Maybe the adhesive can be changed.
3)Some materials will obtain strong viscosity when wetted by water. In this case, ethanol or ethanol solution can be used as adhesive.
