Mixing powders, liquids, semi solids and other products is critical in the pharmaceutical, food, chemical, and dye and beverage industry. The process results to uniform and random arrangement of particles in a given product. Various mixers and blenders have been developed and are widely applied. The common types of blenders include octagonal, cone, double cone, V and bin blenders. Typical mixers on the other hand include; mass and planetary types.Process and Quality aspects
The type of machine used must ensure that the products are adequately combined. This depends on materials, particle sizes, particle cohesion properties as well as shape. Tumble blending is achieved by rotating the container and thereby creating bulk transport and shear. Fixed shell types on the other hand, has a stationary drum while agitation is achieved through the use of moving screws, paddles and blades.
The octagonal blending machine is in a class of its own when it comes to combining dry solids and semisolids products. Notable advantages of these machines are their high blending efficiency, fast mixing process and use of limited space when compared to other machines.
At the heart of this equipment is an octagon shaped outer body with rectangular central portion while the top and bottom have a polygonal frustum. The machine is supported at the ends with bearings and has a drive shaft rotated by an electric motor via a gearbox. The shape of the machine allows for human or automatic loading and unloading of products.
The equipment has many pharmaceutical applications such as homogenizing, blending and lubrication of tablets. Unlike double cone and cone machines that occupy large spaces and only mix a small quantity at a given time, this type uses a small space and three quarter of its volume is filled to ensure high proper mix operation.
The octagon shape and slow speed operation enables efficient lubrication of granules and tablets. For powders, the removable baffles allow fast and efficient mixing. The shape ensures those granules, crystals and other materials move from all sides and this enhances the lubrication and homogenization.
In high pharmaceutical production centers and for sensitive drugs; bin loading system can be added to allow for adding and removal of products in a contact-free and dust free environment. The butterfly valve allows for automatic and manual loading since the valve can be actuated using hands or pneumatic control.Mixers
A wide variety of these machines are used in pharmaceutical industry. They mix wet, dry and lumped materials. The operation is achieved using a specially designed agitator assembly that rotates around its own axis and against a stationary drum. The slow stirring operation inside the container ensures uniform combination of dry and wet products. In addition, fixed or movable blades are also used to increase the agitation process.
Planetary mixers achieve uniform mixing and provide adequate shear for small and medium pharmaceutical firms. The equipment has a vertical offset rotating agitator assembly that rotates against the stationary bowl. The resulting motion is similar to that of the sun and planets. The agitator has blades that provide kneading operation. The small space between the container and blade ensures adequate shearing which enhances the mixing operation.
This article has been written by Arjun Rao, the proprietor of Shree Bhagwati Machtech (India) Pvt Ltd./