Single Barb vs Multiple Barb Fittings          Home | Products | Samples | Orders | Catalogs 
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Eldon James Single Barb Fittings Features
and Clamp Dynamics

Eldon James' 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.

  Eldon James' single-barbed fittings are designed so the mold parting   line stops at the
base of the barb. The ridge and the barb's conical  surface are free of the molded-in leak path
present in multiple barb  fittings. The conical surface on an Eldon James fitting is glass-like
and smooth allowing excellent sealing.

The straight barb shaft provides space for the hose to relax behind the barb causing the clamp
to work like a drawstring. This forces the hose diameter to become smaller than the flare of the
fitting's barb. If the tubing swells from internal pressure (near burst), the clamp will be pulled
up tight to the back of the barb and a tight seal will be maintained.
 A Clamp placed over the Eldon James' exclusive anti-rotation device  (patented),
will lock the tubing, preventing it from being freed by a  twisting motion.
Single Barb Fitting
( Eldon James Fitting)
  
   Multiple Barb   Fitting

  Clamp placement on a single barb fitting.
  Clamp positioning in the recess behind the barb allows for tubing
  compression anterior to the barb and results in a secure seal with   without excessive clamp pressure

 

Clamp placement on a Multiple barb fitting.
Clamp can only be placed over barb. In general, much
more clamp pressure is required to secure a seal than
that necessary with a single barb fitting

Why Multiple Barb Fittings Fail
Mismatches often occur with poor quality or worn tooling, causing misaligned threads and barbs
that result in leakage. With multiple barb fitting designs, it is virtually impossible to avoid creating
parting lines on the barb surface. These parting lines create leak paths which become more
pronounced as the mold tooling wears.
Multiple Barb Fitting - Clamp Dynamics

  1. Clamping on a barb's outer radius, in an attempt to force the
  tube down behind the barbs can cause damage. The sharp edges
  of the barbs become rounded resulting in less bite into the tubing.

  2. Clamping pressure causes the tube to flare out behind the clamp
  and 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
  problem characteristics similar to those shown above. In addition, machinable brass contains
  free lead. Brass parts cannot be used in systems when internal heavy metal contamination is
  undesirable or dangerous.

Updated 10-2007