Pharma Sector

Application

TRP Polymer Solutions manufacture an FDA and USP Class 6-certified FFKM for use in an inflatable ball valve. At four out of the five production plants, the pharmaceutical seal works as expected. At one of the plants, the seal is showing tearing of the teeth of the seal and, in some cases, rupture of the seal as shown in the left photo below. An investigation was initiated by the technical and quality departments.

Problem

Our materials engineers had not encountered this issue previously. They decided to characterise the material within our laboratory and produce data for FEA (Finite Element Analysis). The full cycle of installation and operation was then modelled using FEA. It was observed that at high friction, high stresses are placed onto the areas of concern.

Solution

Having observed that friction may be causing tearing, laboratory tests were undertaken to establish how the friction can be reduced without altering the material itself. Modifying the material would have incurred high costs due to revalidation and equipment downtime.

The tool surface finish was modified to reduce material contact with the housing, reducing the coefficient of friction. The photograph on the left below shows a simple incline plate test, where the improved surface finish produces a lower friction coefficient. Initial testing at the customer has been successful, and long-term testing is still in progress.