Machine Design

Flare-fitting seal withstands higher pressures

Flare fittings have been the connectors of choice for hydraulics systems for over 60 years.

But since then, typical operating pressures have climbed from 1,000 to 5,000 psi. To keep connections leak-free at these pressures, Norm Mathers, an Australian inventor developed the Flaretite seal, which is now made and sold by Flaretite Inc., Fenton, Mich. ( It is said to do away with weeping, galling, face damage, and electrolysis, and compensate for minor surface defects and angular tube misalignments, hence making it leak-free.

The seal is a thin, annular metal stamping coated with Loctite sealant. Five raised concentric rings circle the sealing face. To install, technicians simply snap the seal over the nose of the fitting and torque it to the manufacturer's recommendation. This compresses the raised rings, creating five independent seals across the face of the flare. The compressed rings will also conform to the surfaces below and above it, compensating for scratches, gouges, and misalignments. The compressed rings also maintain the fitting faces in constant compression despite temperature changes and vibrations. The Loctite sealant lubricates the sealing faces which eliminates galling. The lubrication also means applied torque can be higher, which increases the clamping forces on the fitting faces and the integrity of the overall fitting.

The seals are between 0.008 and 0.010-in. thick and made of copper and 304 and 316 stainless steel. They come in 30°, 37°, and 45° flares, and all standard sizes. They can be uncoated, or coated with Loctite Vibra Seal, which withstands temperatures from –40 to 300°F, or graphite, which handles temperatures to 700°F. There is also a permanent anaerobic sealant.

TAGS: Technologies
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