Anonymous writes:
In last couple of years I am hearing from field people and users of DFDC (Double Ferrule Double Compression type fittings) that Swagelok has changed the design of compression fitting to an advanced style compression fitting. This probably was done without the usual publicity associated with any Swagelok new launches.
Many people like me may not be aware of this fact and everyone still assumes a Swagelok fitting is to be a Swagelok fittings. Is there any physical difference between the versions?
Some people with whom I have spoken have remarked that they have observed a sticking effect after making a fitting.Observed sizes were ranging from 1/4" OD / 6mm to 1/2"OD/ 12mm OD Sizes. They further commented that they did not observed this phenomenon a few years.
They further add that after tightening the fitting, properly removing of tube is difficult for checking. This means that for maintenance if this sticking occurs you have to pay additional costs for new fitting
Now a few questions:
1) Is the new design interchangable / intermixable with the old design?
2) If they are, then why are there the differences observed earlier.
First i've heard of it
