When the Swagelok Tube Fitting was introduced in 1947, it was a vast improvement over the other options for connecting tubing to pipe.
But that was 70 years ago. How does Swagelok stay ahead of the competition? Continuous Improvement is a core value.
Over the years, fluid system design has evolved from high volume/low pressure to today’s need for low volume/high pressure. These new demands call for increased internal and external pressures, vacuum levels, flow velocities, vibration levels, shock, and impulses. As a result, the mechanical demands on tube fittings, tubing runs, and other system-related equipment have increased accordingly.
Swagelok remains ahead of the curve to make sure its two-ferrule fitting keeps living up to its global reputation for consistency, quality, and performance. Swagelok has made significant design improvements to its flagship product that it qualified for three design patents. Swagelok’s corporate culture encourages continuous improvement. Everything can always be done better.
Two beats one
So why are two ferrules important in the swaging process? The design provides better tube-gripping action, reduced potential for improper pull-up, improved sealing in gas service, and vastly improved resistance to vibration.
In a two-ferrule tube fitting design, the back ferrule moves the front ferrule forward to spring-load the fitting assembly, burnish and seal with the fitting body, and create the primary tubing seal. The back ferrule also swages the tube to provide the grip needed to keep the fitting and tubing firmly in place. To swage and grip the tube properly, Swagelok’s patented Sat 12 hardening process provides a recessed and contoured geometry of the back ferrule. This process creates a hinging and colleting action that grips the tube and provides more of the back ferrule to be in close contact with the tube to enhance vibration resistance. None of our other competitors use this patented, state-of-the-art process.
Swagelok's two-ferrule system compensates for wide variations in tubing variables, including wall thickness, hardness of the tube, and material. Swagelok also provides a longer sealing path than other designs because of the way the back ferrule lifts up the front ferrule to its sealing position. This sealing position is not in just one point but along the complete surface of the fitting body. The back and front ferrules interact and seal according to the wall thickness, hardness of the tube, and the tolerances on the outside diameter of the tubing.
Because Swagelok created the design and remains the industry leader, some people refer to any two-ferrule fitting as a Swagelok fitting.