Pharmaceutical Mixer
Any process Industry where powders or granular materials are mixed with a liquid the interfacial contact between the primary flow and the secondary flow in the mixing chamber of an eductor determines the mix quality. The core flow interacts with the lobe flow providing rapid dynamic shearing and turbulent mixing. The intense vortices distribution in the mixing chamber of the mixer promotes the full potential of the dry powder or granular additives. Adequate mixing, entraining and dynamic shearing are essential in providing a homogenous product.
Effective blending and mixing are an essential part in pharmaceutical industries. In these applications the requirement may vary but the ultimate achievement is, generally, to have a homogenous pharma products. The various type of pharmaceutical mixer are used in performing more than one function with capability such as suspending solids in a liquid, blending, emulsifying liquids, dissolving polymers, powders and granular materials in a liquid environment.
The utilization of mixing technology in pharmaceutical industries is critical to a broad spectrum of applications. These applications include preparation of APIs, methods of fermentation and cell culture, downstream processing of biological and pharmaceutical operations including suspension handling, and emulsification. Utilization of mixing theory and evolving experimental methods are required for successful development.
Various types of Pharmaceutical Mixers are :
- Laboratory Mixer
- Batch Mixer
- High Speed Mixer
- Mass Mixer
- V Type Blender/ Mixer
- Communiting Mill
Laboratory Mixer
Laboratory mixers are ideal for routine laboratory work, research and development, QA analysis and small scale production in all industries.
Pharmaceutical Laboratory Mixer is suitable for the widest range of applications - mixing, emulsifying, homogenizing, disintegrating, and dissolving - with efficiency and flexibility unmatched by other machines. It offers excellent reproducibility when scaling up to full scale production and provides an accurate and easy means of forecasting the performance under full scale working conditions.
Laboratory mixers are used to mix, emulsify, homogenize, disintegrate and dissolve samples. There are several basic types of products.
- Dual-shaft mixers use a three-wing or helical anchor to generate flow and remove mixed materials from the vessel wall.
- Double-planetary mixers use a rectangular or finger-shaped blade to feed material to an orbiting high speed dispenser (HSD).
- Single-stage rotor/stator devices use a stationary stator to turn an immersed rotor at high speeds. The blades pass each port in the stator and expel material at a high velocity into the surrounding mix.
- Multi-stage rotor/stator mixers increase shearing to produce smaller particle sizes and more homogenous batches. When two to four rotor/stator pairs are nested concentrically, the mixed material that moves outward from the center of the unit is subjected to a rapid, sequential shearing. Some mixers can be operated at variable speeds. Others are designed for continuous speeds.
Selecting Laboratory Mixer
Selecting laboratory mixers requires an analysis of performance specifications.
- Speed range and accuracy are usually measured in revolutions per minute (rpm).
- Viscosity range is measured in cycles per second (cps).
- Capacity, the size of the mixing vessel, is expressed in either liters (L) or gallons (gal).
- Operating temperature and operating range are measured in degrees Fahrenheit (F) or degrees Celsius (C).
- There are two sample introduction methods for laboratory mixers. Continuous devices accept a continuous flow of the sample. By contrast, batch mixers accept only a measured flow or volume. In terms of temperature control, laboratory mixers with an internal heating or cooling elements are commonly available. Heating elements are usually made of ceramic materials, powered electrically, and measured in watts (W). Smooth cooling shovels that rotate within a drum are used to ensure maximum contact without inter-particle friction.
Mixing: Process Technology
For manufacturing pharmaceutical products, as a process technology mixing will create uniformity, decrease gradients or increase mass transfer of materials in bulk. Defining the process is a key to identifying the type of mixer technology required.
Stage Wise Process
- The high-speed rotation of the rotor blades within the precision machined mixing workhead exerts a powerful suction, drawing liquid and solid materials upwards from the bottom of the vessel and into the centre of the workhead.
- Centrifugal force then drives materials towards the periphery of the workhead where they are subjected to a milling action in the precision machined clearance between the ends of the rotor blades and the inner wall of the stator.
- This is followed by intense hydraulic shear as the materials are forced, at high velocity, out through the perforations in the stator and circulated into the main body of the mix.
- The materials expelled from the head are projected radially at high speed towards the sides of the mixing vessel. At the same time, fresh material is continually drawn into the workhead maintaining the mixing cycle. The effect of the horizontal (radial) expulsion and suction into the head is to set up a circulation pattern that minimizes aeration caused by the disturbance of the liquid's surface.
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