Processing Magazine

Double ferrule tube fittings reduce chance of hazardous, expensive leaks

January 23, 2006
High-quality double ferrule instrumentation grade tube fittings provide leak-proof and torque-free seals at all tubing connections. New tube fitting line reduces the chance of hazardous and expensive leaks in instrumentation, process, pneumatic, hydraulic, gas and other tubing systems. It consists of the nut, the back ferrule, the front ferrule and the body, and when installed becomes a five-piece connection with the addition of the tubing providing a solid leak-free joint. The two ferrules are tightly swaged around the tube and the lack of initial strain on the tubing ensures no tubing wall damage. Leaks are prevented because there is an axial movement along the tube instead of a rotary motion creating the joint. This axial movement prevents torque from being transmitted from the fitting to the tubing. Resistant to temperature change, the fittings do not significantly reduce flow area and work with a variety of tube materials. In addition, the two ferrule action supersedes variations in the wall thickness, hardness and dimensional tolerance of the tubes, ultimately compensating for most variables that lead to failure with other fittings.