O-Seal Fittings Information

Application 

UNILOK O-Seal fittings can be directly installed into the existing pipe threads or straight thread ports. As they have short thread length, thread interference does not occur whereas it is common on tapered thread and the leak tightness is obtained by O-ring additionally. The standard Buna-N O-ring has a precision groove, the groove provides anti-extrusion of O-ring at high pressure and controlled squeeze for vacuum tight sealing. To attain a leak tight installation, smooth flat surface perpendicular to the axis of the threads is required. 

Installation Instructions 

1. Hand tighten UNILOK O-Seal fittings into the port until the O-ring compresses on the port. 

2. Wrench-tighten the fittings lightly until the fittings contacts the face of port. Note : The fitting body is always held by back-up wrench when installing or disassembling tubing to or from UNILOK port end to get a proper sealing. 

Mounting Dimensions of O-Seal Fittings 

Fractional(Inch)Tube fittings 

UNILOK fractional(inch) size tube fittings are ordered by part number as shown below. 

Example: The following part number, UMC-0804N-SS, is designated for Male Connector, 1/2"OD x 1/4" Male NPT, 316SS.

Tubing Information  

The proper selection of tubing is essential to assure maximum fitting reliability and performance. When choosing tubing material, size and wall thickness, consider system’s pressure, flow rate, temperature, environment and compatibility with great care. 

Maximum Allowable Working Pressure 

Stainless Steel Tubing 

Fully annealed and seamless stainless steel tubing to comply with ASTM A269 or equivalent. Hardness should not exceed Rb 80. Tubing should be free from scratched and suitable for bending and flaring. 

Copper Tubing 

Fully annealed and seamless stainless steel tubing to comply with ASTM B75 or equivalent. Hardness should not exceed Rb 60. 

Fractional(Inch) Tubing 

Metric Tubing 

For gas service application, use only tubing with wall thickness on outside of gray areas. Allowable stress of 6000 psig between -29℃(-20℉) and 37℃ (100℉) based on ultim ate tensile strength to be 30000 psig. 

Monel Tubing 

Fully annealed and seamless stainless steel tubing to comply with ASTM B165 or equivalent. Hardness should not exceed Rockwell Rb 75. 

Fractional(Inch) Tubing 

For gas service application, use only tubing with wall thickness on outside of gray areas. Allowable stress of 6000 psig between -29℃(-20℉) and 37℃ (100℉) based on ultimate tensile strength to be 30000 psig. 

Determination Factors of MAWP at High Temperature Application 

To determine allowable working pressure at elevated temperature, multiply allowable working pressure and factors which are shown in the table. 

Example: 316SS Tubing, 1/2"ODx0.049"WT at 310℃ AWP: 3750 x 0.85 = 3187 psig.  

* MAWP: Maximum Allowable Working Pressure 

* AWP: Allowable Working Pressure  

Pipe End Thread Information 

The end connections with the lower pressure rating is the determining factor of pressure rating for the fittings with both UNILOK tube ends and pipe thread ends . 

Pressure Rating for Pipe End Thread 

O-Seal Fittings 

Rated to 206 bar (3000 psig) for 316SS fittings up to 1 inch and 25mm 

Kinds of Pipe End Thread

Gaugeability

UNILOK tube fittings are produced with exact and tight tolerances. Without such close tolerances, proper interaction among the nut, ferrules, and body would not occur.

Corrosion Resistance

UNILOK ferrules have the strongest corrosion resistance due to our own special hardening process. 

This has been proven in various industrial areas over several decades.

Interchangeability

UNILOK tube fittings can be interchanged with tube fittings manufactured to international standards.

Less Torque and Anti-Distortion

When the nut is tightened, both ferrules are driven forward between the nut and the body. 

This axial movement doesn't transfer any torque from the fitting to the tubing when the original tubing's mechanical properties are maintained.

UNILOK Tube Fittings Installation Instruction