T
OMEGA’s threads are molded in precision-ground cavities
resulting in perfectly matched threads at the parting line.
While this method is the most costly, it produces the
cleanest, most accurate molded thread possible.
OMEGA’s single-barbed fittings are made so that the moldedin parting line stops at the base of the barb. The ridge and the
conical surface are free of the molded-in leak path. The
conical surface on the fitting is smooth and glass-like, for
excellent sealing.
Why Multiple Barb Fittings Fail
Tooling mismatches often occur in poor-quality fittings causing
mismatched threads and barbs and resulting in leakage.
Tooling cannot be designed to avoid a parting line on multiple
barb fittings. This parting line creates a leak path which
becomes more pronounced as the tool wears.
TYPICAL CLAMPING POSITION
1. Clamping on top of barbs in attempt to force the tube down
behind the barbs can cause damage. It will round off the sharp
edges of the barb and cause it to bite less into the tube.
2. The clamping pressure causes the tube to flare out behind
the clamp. Barbs located behind the clamp will have little or
no effect.
Multiple barbs are typically in close succession. This prevents
the tubing from relaxing to its original size, which is essential
to the barb’s performance. If the tubing does not relax behind
the barb, the barb is rendered useless, as shown above.
(Note the bridging effect.)
ADDITIONAL NOTE: Brass fittings are machined and do not have the problem of molded-in parting lines.
However, brass fittings are usually designed with multiple barbs and have the other problem characteristics
shown above. In addition, machinable brass contains free lead. Brass parts cannot be used on any system if
internal heavy metals are undesirable or dangerous
.
Relaxed tubing behind the
barb is essential to the barb’s
ability to bite into the hose.
Clamping the relaxed hose behind the barb causes the
clamp to work like a drawstring, forcing the diameter of the
hose to become smaller than the flare of the fitting barb.
If the tubing swells from internal pressure (near burst), the
clamp will be pulled up tight to the back of the barb and the seal
will be maintained. When the clamps are placed over the
OMEGA
®
exclusive anti-rotation device the tubing cannot be
freed by a twisting motion.