Parr Instrument 6200 - Manual (Page 13)

Installation
6200 2
w w w . p a r r i n s t . c o m 11
Swagelok Tube Fittings
When Swagelok Tube Fittings are used, the instruc-
tions for installation are:
1. Simply insert the tubing into the Swagelok Tube
Fitting. Make sure that the tubing rests firmly
on the shoulder of the fitting and that the nut is
finger-tight.
2. Before tightening the Swagelok nut, scribe the
nut at the 6 o’clock position.
3. While holding the fitting body steady with a
back-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.
4. For 3/16” and 4mm or smaller tube fittings,
tighten the Swagelok nut 3/4 turns from finger-
tight.
Swagelok tubing connections can be disconnected
and retightened many times. The same reliable leak-
proof seal can be obtained every time the connec-
tion is remade using the simple two-step procedure.
1. Insert the tubing with pre-swaged ferrules into
the fitting body until the front ferrule seats.
2. Tighten the nut by hand. Rotate the nut to the
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 ad-
ditional 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.
Figure 2-1
Swagelok Tube Fittings