Page 61 - D30003

61 Parker Hannifin Corporation
Instrumentation Products Division
Huntsville, AL USA
http://www.parker.com/ipdus
Conical angle allows
dispersement of flow
over more frit surface
Precision tolerance
tube bore for
frit alignment.
FLOW
FLOW
Frit contained in tube bore
by tubing with proper
fitting make up.
Drop in frit allows
accessibility for
micron changes and
cleaning
Pressed in frit eliminates
movement of frit under
pressure or disassembly.
Avoidance of entrapment
areas by flush mounting
frit in counterbore
Precision tolerance
counter bore for
frit assembly
Flow stream contacts
entire frit surface
eliminating
unswept volume
.020 I.D.
.03
.060 90°
6°
Controlled
internal
volume
6.1 X 10 –4 cc
.0135 I.D.
Lead in angle for
frit positioning
Controlled
internal
volume
1.2 X 10–3 cc
15°
.122
.05
Drop In Frit Design
Press In Frit Design
Parker Hannifin’s Instrumentation Products Division offers a
full line of analytical tube fittings. These fittings range from
elbows, tees, and male connectors to low dead volume
unions and column end fittings. Parker incorporates various
features in the column end fittings to effectively address vari-
ous industry concerns.
• Peak symmetry for critical analysis
• Internal volume reduction
As the observed media/substance migrates through the
HPLC column, a “peak” or “band” is created that denotes the
level of concentration. It is critical to maintain peak symme-
try in order to get an accurate reading when processing the
observed media/substance. Parker Hannifin, in the develop-
ment of a line of column end fittings, has incorporated some
key features that help to maintain this “peak symmetry” in
HPLC columns.
“Under most circumstances in liquid chromatography (LC),
the flow through the tube is laminar, the so-called Poiseulle
flow, and in this situation the velocity at all points is parallel
to the tube axis.”
Due to the importance of maintaining smooth laminar flow
after injection of the sample into the HPLC column, Parker
incorporated a small conical angle on the fitting body inter-
nals. This conical angle helps to equally disperse the sample
into the column tube. One of the key requirements of an
effective column end fitting is not to delay or disturb the flow
of the sample through the instrument (HPLC column).
A second area to address is the minimizing of tube fitting
internal “cavities”. A cavity is a short section of the flow path
where the flow-channel diameter increases. It can occur
where tubes are connected to each other (low dead volume
connector) or to injectors, columns (column end fittings), and
detectors. Large cavities can seriously degrade the resolution
of any chromatogram, but they can be easily avoided through
awareness of the geometric design details of the fittings and
connecting parts manufactured by various companies.
Parker Hannifin has incorporated those critical features in both
a low dead volume union connector and the column end fit-
ting bodies. First, the utilization of inverted 1/16" connections
to greatly reduce internal volume or cavities.To eliminate any
confusion or occurrence of incorrect effective tube make-up,
the port depths (body bore dimensions) are identical by size
throughout the entire Parker Hannifin instrumentation line.
Second, Parker closely monitors the dimensions of the small
through-hole utilized in these low dead volume connectors.
D30003 61 5/12/05