Freeze Resistant Gaskets: What Type of Material Should You Use?12 April 2018
A seal fracture is imminent because a gasket has become brittle. The extreme chill has transformed the gasket material into a shadow of its former self. Although all liquefied gasses are moving properly in their pipes and fittings, that system flaw is jeopardizing the whole operation. Beyond question, a freeze resistant gasket should have been fitted. Having said that, is there a material type that can defy such stone-cold conditions?
Most elastomers harden and become less deformable when they encounter subzero fluids. That stiffened seal simply can’t support a pressurized load when the temperature drops this low. Regular silicones are designed to endure when the chill hits -60°C, which is extremely cold. Phenyl silicone keeps on performing, even when the fluid’s temperature hurtles towards -100°C.
PTFE or Teflon Gaskets
Manufactured under the brand name Teflon, Polytetrafluoroethylene based seals perform well when they’re utilized in cryonic cooling environments. Penetrating below -100°C and barreling down towards -185°C, Teflon doesn’t stiffen when these extremes are accessed. Beware, PTFE gaskets do experience creep when they’re pressed into service as low-temperature fluid seals.
Freeze Resistant Tungsten Carbide
For abrasion proof functionality, tungsten carbide is the logical low temperature sealing material. Sintered graphite is often used as a compressible face here, so this is a composite gasket group. Expect to find ceramics and other exotic metals employed as key freeze choking materials when the tungsten carbide catalogue is accessed. Selected when harsh chemicals are present in the cold fluid, the material also endures when abrasive forces are being processed.
All about Grafoil Gaskets
Also known as flexible graphite, Grafoil gaskets retain their operational properties until the deep freeze strikes -240°C. The chemically formed rings conform well to their installation surfaces. However, Grafoil isn’t as pliable as a synthetic polymer, so these gaskets must be manufactured according to a high-tolerance fabrication methodology. Designed to handle wide temperature extremes, Grafoil gaskets do not tolerate misalignment errors.
Low-temperature seals employ natural and synthetic polymers when a liquidized gas manifests a subzero thermal profile. If that thermal reading then drops below -100°C, the joining faces turn to flexible graphite, to composites and exotic metals. Ceramic inserts are also on hand when these gaskets face the brittleness test. The polymers, as expected, are pliable, not stiff, when the flow is supercold. Meanwhile, the harder composite solutions deal with the severest temperature drops, but they must be manufactured precisely, for they won’t adapt when compressed, at least not as well as a synthetic rubber would manage.
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