High Temperature Resistant ‘O’ Rings Extend Glass Cutting Production

High performance ‘O’ rings available in the UK from Dichtomatik Ltd have increased performance and productivity in glass tube cutting operations.

The production of pharmaceutical glass containers has traditionally involved specialised equipment for the precision heating, bending and cutting of long glass tubes. During the manufacturing process, the tubing is rotated by a stainless steel wheel which incorporates an external ‘O’ ring to prevent direct contact between the steel and a hot glass surface. Due to the high thermal conductivity, metal contact can damage glass at elevated temperatures, and in such an environment specially formulated temperature resistant silicone ‘O’ rings have traditionally been used.

With typical glass temperatures during production of 446°F (230°C), silicone ‘O’ rings had a limited operating lifetime of days (one week maximum), due to the thermal degradation that occurs. This degradation leads to marks occurring on the glass tube surface, resulting in rejection of the manufactured product. This scrapped production compromises efficiency, replacing ‘O’ rings also reduces plant uptime, resulting in a considerable increase of production costs overall.

However, purpose designed DuPont™ Kalrez® Spectrum™ 7090 ‘O’ ring replacement parts, available from Dichtomatik Ltd, not only extend the MTBF life of these products to over 6 months, while at the same time also eliminating ‘O’ ring degradation during this period. The Kalrez® 7090 parts offered an excellent combination of chemical and thermal resistance, up to 617°F (325°C). Frequent ‘O’ ring replacement was eliminated, as well as product scrappage, with plant downtime being substantially reduced and overall plant yield boosted.

The Kalrez® range of perfluoroelastomer ‘O’ rings are part of the DuPont™ Performance Polymers range, formulated to provide superior operating and sealing qualities for even the most difficult applications. These speciality black parts offer outstanding thermal stability and chemical resistance for continuous service at elevated temperatures. For applications where gas/liquid sealing qualities are required, then excellent mechanical properties of high hardness/higher modulus are combined with compression set resistance, providing both static and dynamic sealing together with high extrusion resistance. Seal force retention and rapid gas decompression resistance is also achieved when operating in conditions where temperature cycling effects occur.