FEP O-Rings solve sealing problems in pharmaceutical & cosmetics processing

24-Mar-2005

The difficulty of sealing within vacuum mixing and homogenising plants used in pharmaceutical and cosmetics industry processing led Busak+Shamban engineers to research an FEP encapsulated O-Ring solution. The primary problem with the use of ordinary elastomer O-Rings in this field of application is the seal’s inability to retain integrity when harsh chemicals are used in CIP (cleaning in process) and SIP (sterilisation in place) processes. Essentially, the O-Ring must achieve a small axial direction but, following cleaning processes, elastomer O-Rings are inclined to stick within the groove housing.

The FEP O-Ring consists of an elastomer inner ring and a seamless FEP encapsulation sheath around this. The desired elasticity is provided by the elastomer ring and the chemical resistance by the seamless FEP sheath. The seal is usually used as a secondary sealing element in conjunction with mechanical seals.

For this specific area of pharmaceutical and cosmetic processing, the task was to provide effective sealing to cope with harsh cleaning procedures, to operate at pressures from vacuum to 3 bar and tolerate temperatures up to 155 ºC. The surface roughness of the housing was Ra 0.1 to Ra 0.4 and the O-Ring inner diameters were from 25 to 135 mm. No change in groove design was permitted.

 The FEP encapsulated O-Rings solution provided by Busak+Shamban for this demanding application, comprised of an inner ring in FKM material (to cope with a temperature range –20 ºC to 200 ºC) and VMQ material (to cope with a temperature range –60 ºC to 200 ºC), with the outer sheath material in thermoplastically mouldable Tetraflourethylenhexaflouropropylene FEP.

 Inherent qualities of FEP encapsulation provided a reduced friction force, excellent resistance to most liquids and gases, resistance to abrasion and conformity to FDA regulations.