Page 361 - BOLA Catalogue

TECHNICAL INFORMATION
Tubing - Choice and Assembly Choice of wall thickness
When choosing the wall thickness, a couple of issues have to be consi- dered:
» What max. pressure will be applied?
In the charts on page 292 the minimum wall thickness can be easily found.
» To which temperatures will the tubing be exposed?
The maximum pressure has to be reduced by the on page 292 stated reduction factors.
» Shall the tubing be applied under vacuum?
Then the wall thickness has to be sufficient (rule of thumb).
Fitting and tubing have to fit
Practice has proved that tubing varies in diameter. We therefore recom- mend to check before assembly whether the tubing outer diameter corres- ponds to the nominal size (e. g. Ø 6 mm). The values in the right chart will be helpful.
The surface of PTFE tubing can be damaged if V-rings are inserted by force and result in leakage.
Transition from imperial to metric tubing
With BOLA Tube Fittings and Reducing Unions, transition from imperial
to metric tubing or connections between both can easily be made. For example: A pipe socket of an analytical device with an outer diameter of 1/4“ shall be connected to a PTFE tubing with an outer diameter of 8 mm. Needed components: Reducing union 6 mm to 8 mm (Cat.No. D 526-10) and a set of tapered V-rings Ø 1/4“ (6.35 mm; Cat.No. D 502-03).
By exchanging the 6 mm V-rings with the 1/4“ V-rings, the pipe socket can be connected to the 1/4“ reducing union and the 8 mm PTFE tubing on the other side.
Rule of thumb for determination of wall thickness:
outer-Ø x 0.1 = wall thickness
For a “normal” use in the lab without thermal load or pressure, a wall thickness of 10-15 % of the outer diameter of the chosen tubing is sufficient and offers a certain security.
E. g. for a PTFE-tubing with outer diameter 8 mm the wall thickness should be 0,8-0,9 mm respectively rounded up to the next bigger standard wall-thickness of our range.
Nominal-Ø of screw joint in mm
0.5–3,2
4.0–14
> 16
Recommended max. tolerance of tube/tubing in
± 0.05
± 0.1
± 0,25
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