Using O-ring face seal fittings (ORFS or flat face fittings) such as Parker Seal-Lok is one of the easy steps you can take to get rid of hydraulic leaks in your hydraulic system. Hydraulic leaks are mostly viewed as a nuisance but the drops can add up to real money fast. (Read about cost of hydraulic leaks in our related blog.)
The O-ring face seal technology was pioneered by Parker's tube division in the early 1980s.
The fitting consists of a nut, a body, an O-ring and a sleeve. It meets or exceeds the requirements of SAE J1453 (for imperial sizes) and ISO 8434-3 (for metric sizes). Parker produces over 60 body configurations of Seal-Lok tube fittings for all kinds of applications.
The tube is flanged to 90° or brazed to a sleeve. The body face contains a high durometer O-ring held captive in a captive O-ring groove. As the nut is tightened on to the fitting body, the O-ring is compressed between the body and the flat face of the flanged tube (or brazed sleeve). As the fitting is assembled, an O-ring is compressed and eventually "fills-out" the precision machined groove in the fitting body to form a leak tight seal. As the face of the tube comes in contact with the face of the fitting body, further tightening of the nut will cause the assembler to sense a sharp rise in torque. It is a signal that the assembly has been made and a solid pull of the wrench at this point to the recommended tightening torque produces a tight, positive seal. Because of this sharp rise in torque when the two faces meet, the possibility of over tightening is minimized.
Since the flat sealing surfaces are perpendicular to the assembly pull, they remain virtually free of distortion during assembly and consequently permit Seal-Lok to be re-made over and over.
The Seal-Lok fitting is also suitable for hose assemblies.
If you have a compatibility issue with the standard O-ring, you can use a non-standard O-ring to suit your application. Choose from fluorocarbon compound or Nitrile compound. If that does not do the trick, you may have to resort to using a 37° JIC flare fitting (like Parker Triple-lok®).
Follow this link for more information on Parker Seal-Lok.
Posted by Marek Bobik