Why does a compression fitting have a single symmetrical ferrule?
This is because in a compression fitting with a single symmetrical ferrule, it’s possible for the nut to transfer torque to the ferrule as it is tightened. This torque can cause the ferrule to compress asymmetrically or shift over time.
How is the shape of a compression fitting important?
The shape of both the ferrule and the mating angle of the fitting body are critical factors in the reliability of a compression seal. Both components must be tapered in a manner that allows the ferrule to compress properly as the nut is tightened, while maintaining axial alignment with the tubing.
How is torque transferred from compression nut to ferrule?
With harder materials like steel however, torque is often transferred from the compression nut to the ferrule as the nut is tightened. The resulting rotation can cause the ferrule to compress asymmetrically, or to shift over time due to residual torque.
What’s the difference between two and one piece compression fittings?
One Piece vs. Two Piece Ferrules. Most basic compression fittings contain a single ferrule. Single ferrule designs minimize the total number of components, and work reliably when fabricated from softer materials (plastic or brass for example).
This is because in a compression fitting with a single symmetrical ferrule, it’s possible for the nut to transfer torque to the ferrule as it is tightened. This torque can cause the ferrule to compress asymmetrically or shift over time.
The shape of both the ferrule and the mating angle of the fitting body are critical factors in the reliability of a compression seal. Both components must be tapered in a manner that allows the ferrule to compress properly as the nut is tightened, while maintaining axial alignment with the tubing.
With harder materials like steel however, torque is often transferred from the compression nut to the ferrule as the nut is tightened. The resulting rotation can cause the ferrule to compress asymmetrically, or to shift over time due to residual torque.
What kind of materials are used in compression fittings?
Ferrules The ferrule is the primary sealing component of a compression fitting assembly, and they can be found in a wide variety of materials ranging from stainless steel to graphite. The majority of ferrules in the marketplace however, are manufactured from metals.
