The simple test sieve is the most basic and cost-effective type of particle-size analyzer on the market. For this reason, it is an important weapon in the battle to maintain rigorous Quality Control standards. Due to its simple, yet highly effective design, this type of particle-size analyzer plays an important role in many production facilities, including those found in the pharmaceutical, food processing, cosmetic, agricultural and chemical processing industries.
In general, a particle-size analyzer is used to determine the overall composition of dry, granular materials (e.g., cosmetic face powder or whole wheat flour). In addition, fluids containing solid particles held in suspension, such as chemical slurries and household paint, can also be evaluated in this manner. Regardless of the material being tested, a particle-size analyzer is used to determine the size, shape and distribution of particles present within any given sample of that material.
When compared to other particle-size testing options, sieve testing offers a number of distinct advantages. However, this method does present a few drawbacks, as well.
Advantages of Using Test Sieves for Particle Size Analysis
* Inexpensive. Thanks to their straightforward and uncomplicated design, test sieves are much less costly than more sophisticated, computerized models. This makes them the ideal solution for many manufacturers who need to keep an eye on quality, without needing to invest in a higher-end particle-size analyzer.
* Produce Consistent and Reliable Results. In spite of their simple design, test sieves are able to produce repeatable results regardless of when or where each test is performed. This is of great value to Quality Control managers who depend upon the accuracy of these tests to maintain the integrity of the production process.
* Readily Available. Thanks again to their simple design, test sieves are easy to obtain. This makes them very easy to replace when necessary, with no lost production time due to difficult-to-find parts.
Disadvantages Associated with Employing Test Sieves
* Dependent on Consistent Energy Input. In order to conduct a sieve test, the test sample must be “shaken” in order to separate out the smaller particles from the larger ones. As a result, the only way to produce consistent, repeatable results using this method is to apply the same degree of “shaking” (energy) across all testing scenarios. Mechanical sieve shakers are available to help alleviate this concern. However, there are currently no industry-wide standards governing the calibration of these units. Therefore, in-house calibration standards need to be developed and maintained by the facilities employing them.
* Static Electricity. Static electricity can cause fine particles to adhere to the wire mesh of the test sieve. This, in turn, can skew results and lead to incorrect analysis data. Fortunately, the addition of talc, activated charcoal, activated magnesium or burgess clay can greatly reduce the impact of static electricity on the final testing results.
Clearly, there are a number of pros and cons associated with using a simple test sieve for particle size analysis. However, many Quality Control professionals have come to rely upon them in order to maintain production standards in a wide range of environments.
