Skip to main content

Renin Angiotensin Mechanism.

V Cone Blender.

 

Principle:

  • It's a “Tumbling Mixer”.

  • It works on the mechanism of Diffusive Mixing.

Construction:

  •  Also called “Twin Shell Blender”.

  • It consists of two vessels which are attached at the ends at 70 to90 degree angle as shown in the figure.

  • It is made up of stainless steel or complete plastic.

  • The blender is mounted on a metal frame on which it can be rotated.

  • Sometimes baffles are attached inside for thorough mixing.

  • The openings are used as inlet ports while it is unloaded through the discharge port at the bottom.

Working:

  • The materials to be mixed are introduced to the mixer through one of the ports.

  • The mixer is loaded approximately two thirds of the volume to allow tumbling of the powders.

  • When the mixer is started, it rotates along the axis and when the V is inverted, the material splits into two portions and undergoes tumbling.

  • The tumbling movement during rotations causes mixing.

  • The speed of the mixer plays an important role in the mixing,

    • If rotations are slow: Mixing will not take place as materials will just glide over one another.

    • If rotations are very fast it will cause generation of centrifugal forces hence powders will remain adhered to the walls and hence no mixing will take place.

    • For better results the V cone blender needs to be operated at an optimum speed.

Uses:

  1. For mixing a variety of powders and granules.

Advantages:

  1. Minimum attrition and hence good for fragile granules.

  2. Easy to clean, load and unload.

  3. Minimum maintenance cost.

  4. Available in different sizes.

Disadvantages:

  1. More space is required.

  2. No application of shear and hence not useful for materials with large particle size distribution.

  3. Suitable for free flowing powders and granules only.

Commonly Asked Questions:

  1. Define Mixing. With help of a diagram describe the principle, construction and working of the V Cone Blender.

  2. Write a short note on V Cone Blender.

Popular posts from this blog

Rate of Drying Curve.

  Definition Drying is defined as the removal of liquid from a product usually with application of heat. Rate of Drying Curve. Drying process can be divided into three periods Initial Adjustment Period. Constant drying rate period. First falling drying rate period. Second falling rate period. Initial Adjustment Period (A-B): Also called the “ Heating up” period . In this period the substance gets heat and increases in temperature. Drying has not yet started. Constant drying rate period (B-C): During this period the temperature of the solid and the rate of drying remain constant. The moisture evaporating from the surface is replaced by water diffusing from the interior of the solid at a rate equal t o the rate of evaporation.  The moisture content at the end of constant rate (point C) is referred to as the critical moisture content (CMC).  At CMC, dry spots start appearing and drying rate starts falling . First falling drying rate period (C-D): This period is also called the period of

Heat Exchangers and Heat Interchangers.

  In pharmaceutical industries many types of equipments are used for transfer of heat, they can be classified as follows, Heat Exchangers. Heat Interchangers. Heat Exchangers: These devices are used for transferring heat from a fluid (Hot Gas or Steam) to another fluid (Liquid) through a metal wall. Heat Interchangers: These devices are used for transferring heat from a One liquid to another liquid or one gas to another gas through a metal wall. HEAT EXCHANGERS; The equipment used for heat transferring are known as heat exchangers. Some of the processes that involves heat transfer in pharmaceutical industries are: Preparation of starch paste (in steam jacketed kettle). Crystallization. Evaporation. Distillation.  Classification of heat exchangers On the basis of transfer of heat, heat exchangers are classified as: Direct transfer type:  The hot and cold fluids are separated by a metal wall through which the heat is transferred from hot fluid to cold fluid. E.g. shell and tube heater, 

Flash Distillation.

  Principle: When a hot mixture is allowed to enter from a high-pressure zone into a low pressure zone, the entire liquid mixture is suddenly vaporized. This process is known as flash vaporization .  During this process, the chamber is cooled.  The less volatile fraction is condensed and the more volatile component remains in the vapor phase .  This process requires time, hence liquid and vapor are kept in intimate contact until equilibrium is achieved. Flash distillation is also called equilibrium distillation because separation of two liquids takes place when liquid and vapor phases are at equilibrium. Equipment used for Flash Distillation: Construction: It consists of a pump, which is connected to a feed reservoir.  Pumps help in pumping the feed into the heating chamber.  The heating chamber is heat supplied by steam.  The other end of the pipe is directly introduced into the vapor-liquid separator through a reducing valve.  The vapor outlet is provided at the top of the separato