Page 359 - BOLA Catalogue

TECHNICAL INFORMATION
Tubing - Notes
Thin hoses for vacuum or high temperatures
We recommend to support the tubes in the area of the laboratory screwing for high temperatures, vacuum operation or thin wall thickness. This can be done using a glass or metal tube section. This prevents that the tube can swerve inwards and become leaky. With this trick it is also possible to fix elastic, rubbery tubes at glass threads with the BOLA laboratory screwing.
Tolerances for BOLA Tubes
The tubes mentioned match exactly to the BOLA Screwing Systems. Therefore, you can be sure that all fittings and screwing fit together. The practise showed that tubes show a certain tolerance as to external dia- meter and the wall thickness. The tubes mentioned are checked several times. The basis for this are strong BOLA internal standards which go far beyond the usual market requirements as to quality and measurements.
Beside the outer diameter of a tube, the wall thickness is also important for the quality evaluation. We at BOLA, have also set a stronger tole- rance for the wall thickness than typically applied. Above all, we do not allow that due to chaining of tolerances the tube gets a totally different measurement than actually required. Therefore, the wall thickness of the BOLA tubes may vary only within the tolerance of the outer diameter as mentioned in the table beside.
Furthermore, the tubes are controlled that there are no material faults (e.g., inclusions of foreign particles), lengthwise grooves and/or gross grooves, and no unevenness at the outer and inner diameter.
Tolerances for Pure, Unfilled PTFE, PFA, FEP Tubes
Nominal outer diameter mm
0,4–2,9
3,0–10,0
10,1–16,0
16,1–22,0
über 22,1
Tolerance outer diameter mm
± 0,05
± 0,10
± 0,15
± 0,20
± 0,20
Wall thickness
mm
0,1–0,3
0,4–1,0
1,1–2,0
über 2,1
Tolerance
mm
± 0,025
± 0,05
± 0,10
± 0,20
Tolerances for antistatic ex-proof tubes, PTFE-EX
Nominal outer diameter mm
1,6–3,2
3,3–6,35
8,0–14,0
16,0
Tolerance outer diameter mm
± 0,10
± 0,25
± 0,30
± 0,40
Wall thickness
mm
0,4–0,8
1,0
Tolerance
mm
± 0,10
± 0,20
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