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 Ordering Information
NOTE: The design has three key elements.
- The use of identically shaped ferrules.
- The ferrules are of a very similar material as the tubing.
- The ‘ferrule chamfer’ in the body matches the shape of the ferrule chamfer in a standard HPLC port.
- Replacement ferrules.
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UHPLC Fitting for Peek and Peeksil Tubing
Biocompatible Fittings
A new fitting design has been developed which extends the practical pressure limits of PEEK and PEEKSil tubing.
In summary, the upper limit had previously been approximately 7000 (or so) PSI (450-500 BAR). The new fitting
has been demonstrated to hold PEEK tubing at 10,000 PSI, and PEEKSil to over 15,000.
Background: The mechanical properties of PEEK indicate it is capable of bearing significantly higher
pressures than the published limit of 7000 PSI. Seldom are high pressure failures involving PEEK tubing
manifested in deformation and rupture of the tubing itself. Rather, failures are usually observed as slipping
of the tubing.
By making conventional fittings extraordinarily tight, and by using a variety of conventional fitting types,
varying failure pressures can be observed from 4000 PSI up to the 7000 PSI limit. After use, examinations of
tubing show deformation of the tubing in the area of the ferrule area which is somewhat correlated to the
failure pressure.
Solution: Increasing the amount of surface area that grips the tubing will increase the pressure at
which the tubing slips. Additionally, a ferrule material as similar to the tubing itself would allow for
uniform deformation of both the tubing and ferrule. The design of these fittings uses two identical ferrules,
and two nearly identical compression surfaces. That is, the conical area, or ‘ferrule chamfer’, into which the
ferrule is compressed, is as identical as possible to that of a standard HPLC port. The overall fitting
assembly is shown in exploded form below.
When installed, these three elements work together to assure a maximum gripping area is utilized and that
the compliance of the ferrules is such, being of the same material as the tubing, that minimal tubing
deformation occurs.
Installation: Prior to installing in an HPLC port, the ‘body’ and ‘cap’ are screwed together, capturing
a ferrule inside the fitting. Tightening the cap slightly against the body will allow the fitting to grip the
tubing so it may be inserted to the bottom of the HPLC port. The external ferrule is then placed over the
tubing end and the fitting is ready to install. Installation proceeds by grasping the cap and pushing the
fitting into the port while turning the cap. The cap can be The fitting described in this report is Patent
Pending.
The cap can be tightened very firmly and the action of the system assures even pressure will be applied to
both ferrules.
Never use a wrench to install the fitting. The hex area of the fitting is provide for removal only.
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