Essentially Rubber: Better drinking water sealed
17 Aug 2023
Leading-edge designs and applications showing how elastomer materials contribute to all aspects of life and lifestyle in the 21st century:
Freudenberg Sealing Technologies (FST) has developed a patented urethane seal for water-purification and carbonated-water appliances that accommodates different valve dimensions and offers high impermeability under pressure.
The valves are screwed into water purifiers with a standardised trapezoidal thread, while a pressure reducer on the appliance lowers the cartridge pressure from 60 bar to a permanent working pressure of around 3 bar.
When the water purifier is used, the pressure quickly decreases, and the gas abruptly expands. During this rapid decompression, the gas in the material escapes back out of the material.
If the right material is not used, gas can accumulate in the seal or the expansion could create bubbles and damage the seal, FST explained. The seal must also "compensate for the various connection dimensions of the valves on the gas cartridges and make it easy for users to change the cartridges.”
Here, “a clever combination of material and geometry ensures the lowest possible frictional torque as the cartridge is twisted in or out.” For the seal, FST used its polyurethane grade 93 AU V167 as it is “very elastic, wear-resistant and approved for food contact.”
