Parr Instrument Company 6300, Operating Instructions Manual

Page: 15 / 130

I
NSTALLATION
6300
2
w w w . p a r r i n s t . c o m
15
Fitting. Make sure that the tubing rests firmly on
the shoulder of the fitting and that the nut is finger-
tight.
Before tightening the Swagelok nut, scribe the nut at
2.
the 6 o’clock position.
While holding the fitting body steady with a back-
3.
up wrench, tighten the nut 1-1/4 turns. Watch the
scribe mark, make one complete revolution and
continue to the 9 o’clock position.
For 3/16” and 4mm or smaller tube fittings, tighten
4.
the Swagelok nut 3/4 turns from finger-tight.
Figure 2-1
Swagelok Tube Fittings
R
ETIGHTENING
S
WAGELOK
T
UBE
F
ITTINGS
Swagelok tubing connections can be disconnected
and retightened many times. The same reliable leak-
proof seal can be obtained every time the connection is
remade using the simple two-step procedure.
Insert the tubing with pre-swaged ferrules into the 1.
fitting body until the front ferrule seats.
Tighten the nut by hand. Rotate the nut to the
2.
original position with a wrench. An increase
in resistance will be encountered at the original
position. Then tighten slightly with a wrench.
Smaller tube sizes (up to 3/16” or 4mm) take less
tightening to reach the original position than larger
tube sizes.
The type of tubing and the wall thickness also has an
effect on the amount of tightening required. Plastic
tubing requires a minimal amount of additional
tightening while heavy wall metal tubing may require
somewhat more tightening. In general, the nut only
needs to be tightened about 1/8 turn beyond finger tight
where the ferrule seats in order to obtain a tight seal.
Over tightening the nut should be avoided. Over
tightening the nut causes distortion (flaring) of the lip
of the tube fitting where the ferrule seats. This in turn
causes the threaded portion of the body to deform. It
becomes difficult to tighten the nut by hand during a
subsequent re-tightening when the fitting body becomes
distorted in this manner.