When compared with rightly installed and selected hard metallic tubing, flexible tubing is much more susceptible to leaks from abrasion, chemical abuse, vibration, etc. The regular transmission and flexibility of vibrations as well as movement to the sealing area of the push-to-connect air fitting appear to limit and reduce its active life.
The normal push-to-connect air fittings can show relative movement by the tube on the retainer (also known as grippers) and O-ring when they are subjected to vibrations. This will prompt wear problems thus leading to a higher susceptibility to leak. At a point, the fittings useful life becomes useless when both the seal areas and retainer are too damaged. Some designs make use of ribbed seal material rather than O-rings.
The back ferrule supports tubing in place with the double ferrule sealing wedge design. The wedge seal situated on the tubing is pushed by the front ferrule, formed by the back ferrule, as the air fitting gets tightened. There is very small (if any) relative movement between the tubing and fitting and tubing – therefore wear is limited. This design shows dependable durability as any wear that could happen can be offset with a little amount of tightening easily.
Investigating Pneumatic Fittings and Tubing
It would be to the advantage of any plants that the inlet compressed pressure and air flow to any production machinery be monitored using an evident number of fittings and tubing. Possibly set a “Best Practice” standard for compressed air use when completely repaired or new. Thereafter monitor compressed pressure and air flow for diversions from the “Best Practice Flow and Pressure”. Any diversion will offer a good pointer of compressed air leaks to be repaired.
So as to arrive at the aforementioned “Best Practice” scenario, the size and type of the operating tubing should be reviewed as well. We have seen cases where productivity dropped or pressure increased because ¼” nylon tubing replaced ¼” copper tubing and was not able to deliver an equivalent amount of compressed air flow at required pressure levels.