If there is one industry that really needs hygienic and efficient processes it is the pharmaceutical industry. The approval of the use of any drug must follow strict biosafety protocols to guarantee the purity of its components, both active principal ingredients and excipients.
One of the main processes used by the pharmaceutical industry to achieve the required quality is sieving. This is a physical method of separating mixtures of particles of different sizes by passing them through meshes of different aperture sizes. This screening method allows particles larger than a certain size to be retained, while particles of the appropriate size can pass through.
Screening or sieving is a particle separation technique used since ancient times, which today has reached great sophistication of the equipment used. Also, there are different standards that regulate some of their operation features, like the sieve opening diameter regulated by ISO standards.
In the pharmaceutical industry, screening or sieving has applications in the control of powdered ingredients before mixing, in the elimination of contaminants and in the classification of the granules produced.
Non-vibrating screens vs. vibrating screens
What are non-vibrating screens?
As their name indicates, non-vibrating screens perform their function without the use of vibrating movements, only based on the force of gravity. They were traditional forms of screening until recent times, consisting of a fixed screen with a steep inclination. Today the non-vibrating screens have been displaced by vibrating screens in which gravity is combined with the vibration movement.
What are vibrating screens?
In Vibrating Screens, the vibratory motion is coupled with gravity to make the screening process more efficient. With vibration, the particles of the product placed on the screen mesh jump and hit against the screen openings, more likely to pass through.
Process efficiency is expressed as a percentage. The vibrating screen never reaches 100% efficiency because it would require an extremely long process. However, the most modern equipment achieves high percentages, acceptable for what is required.
Efficiency is calculated as the proportion by weight of the particles that passed out of the total weight of product placed on the screen, expressed as a percentage.
