How to convert 37-degree hydraulic fittings into zero-leak connections

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The 37-degree hydraulic fitting is the world's most commonly used hydraulic connection. This popularity is due to its ease of fabrication, wide size range, adaptability to metric tubing and worldwide availability. For over fifty years, it has been the hydraulic fitting of choice for hydraulic system manufacturers.

But as technology has improved and hydraulic system pressures have steadily increased, the flared fitting has become prone to leaks and drips, which results in dirty, sludge-covered systems that give hydraulics a bad name. The cost of hydraulic oil leaks to industry and the environment is only now being fully considered.

Alternative hydraulic fittings are gaining acceptance, most notably the 'O-Ring Face Seal' (ORFS). The ORFS fitting has significantly improved the integrity of hydraulic connections, but at a cost. It is larger in size, offers fewer adapter options, is more difficult to install (alignment must be perfect or O-ring extrusion occurs), has limited worldwide availability, is twice the price of a flared connection, and the O-ring is susceptible to heat damage.

A new sealing device has propelled the old, flared connection into the new "no-leak" world demanded by modern hydraulic systems. The Flaretite Seal is a stainless steel stamping, designed with multiple, concentric rings. The entire seal is impregnated with a baked-on Loctite coating. When inserted into a flared hydraulic fitting, the concentric rings form multiple seals down the face of the flare and the Loctite coating fills minor imperfections. The sealing rings prevent debris and aggressive cleaning solvents from attacking the sealing face and also protect the face from fretting, galling and over-tightening. And unlike the ORFS fittings, it will not fail during a fire. This prevents atomized hydraulic oil from fueling combustion.

Flaretite hydraulic fitting seal.

Flaretite Seals are easy to install. They snap onto the male end of the flare and the hydraulic fitting is tightened in the usual way. The result is a permanent, zero-leak connection which exceeds the performance of today's ORFS fittings, at significantly less cost.

Related articles:

Why you should record all hydraulic oil top-offs
Something to think about next time you change a hydraulic hose
How to deal with hydraulic and pneumatic leaks

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