Plansifters Optimal Sizing of Pellets
Losan Pharma with its head office in Neuenburg, Germany is an internationally recognised partner of the pharmaceutical industry that uses among others Siftomat plansifters manufactured by Fuchs Maschinen to produce high quality pellets.
Before deciding to use a Siftomat plansifter for sizing the pellets, the company went through an evaluation and testing programme of various sifters, from which Siftomat emerged as the most suitable machine for the intended use. The aim of these tests was to determine the efficiency of the plansifters related to the product to be processed and the extremely high quality requirements of the company regarding variations in quality of coated pellet batches.
During this sizing process, undesired fractions have to be removed in order to obtain an impeccable and consistent quality of the product. More concretely, over- and undersized particles are sized and removed from the ‘good’ particles of the product. When it comes to process 400 kg per hour and 360 hours every year, no compromise can be allowed. Another key argument in favour of the plansifter is its absolute proven reliability as no breakdown occurred since it was commissioned, states the firm.
For applications in the pharmaceutical industry, the plansifter version in stainless steel and closed housing are required. All product wetted parts are mainly of stainless steel (1.4301), all others in glass pearl blasted stainless steel (1.4301), the motor being completely integrated in the raised machine base. Sealing between the machine base and the driving cylinder is carried out by a highly resistant tightening sleeve along with a zipper.
According to the company, the plansifter can be fitted to carry out sizing up to four fractions. In the present case only three fractions are required: oversized and ‘good’ particles, dust or undersized particles with meshes between 0,16 and 2,5 mm. With its low installation, height integration of the machine in existing production lines is easy and coping with the required performance is not an issue.
The machine is based on a straightforward working principle. An eccentric drive makes the sieves swing in a plane eccentric movement. The coarse product that has to be sifted passes over the sieve mesh while the fine product falls through the mesh. Siftomat offers the advantage of processing gently. Furthermore, the pure plan sifting movement shows a positive effect on the sifting quality.
Setting the machine for optimum sifting is extremely simple, only the slope of the sieves has to be adjusted. For higher throughputs with good flowing products, one should increase the sieve slope. On small and middle-sized sifters one just has to loosen two screws, and on bigger machines eight screws. The optimum sieve slope is factory set and normally does not require any further adjustment. This also applies to the machine speed, mentions the firm. In special cases and with more demanding products, where bulk products must be sorted according to their length, the use of a frequency converter is required.
In the pharmaceutical industry where hygiene is an absolute priority, machines must be easy to clean. The plansifter is made in its closed version entirely of stainless steel and can be easily dismounted and cleaned without the use of tools. This guarantees minimal downtimes and the best possible hygiene. Furthermore, it is also simple to remove the sieves and the spacer frames to clean the sieve case and place them back again. The Siftomat is also available in its Siftomat mini version with the same functionalities as its ‘elder sister’ for sifting small batches up to 100 kg, concludes the company.