Choice and Assembly
Choice of wall thickness
When choosing the wall thickness, a couple of issues have to be considered:
- What max. pressure » will be applied? In the charts on page 226 the minimum wall thickness can easily be found.
- To which temperatures will the tubing be exposed? The maximum pressure has to be reduced by the stated 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 recommend to check before assembly whether the tubing outer diameter corresponds 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.
First check whether your laboratory screw joint (inner diameter) fits your tubing (outer diameter). If it is still difficult to put the tubing inside the inner parts of the laboratory screw joint, a trick can be helpful. Just either sharpen the tubing with a simple sharpener or cut it diagonally. You should now be able to easily put the tubing through the inner parts.
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 O 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.
BOLA Laboratory Screw Joints
BOLA Laboratory Screw Joints are the perfect choice to connect hardwalled tubing (e. g. PTFE, PFA, FEP) or tubes in different materials (such as glass, metall, plastics) with devices with GL-threads.
Each laboratory screw joint consists of a cap with female GL-thread, bore and internal cone as well as a set of three inner parts: v-ring, tapered ring and sealing ring. For laboratory screw joints for tubing O. D. smaller than 3 mm, the sealing ring includes additionally a FPM-o-ring which is protected by a PTFE sealing lip. The special clou of BOLA’s Laboratory Screw Joint System: You can connect different tubing diameters to the same GL thread by simply exchanging the inner spare parts. It is not necessary to adapt the GL thread or fitting. A reduction is made by exchanging the inner spare parts instead of adapting the GL thread.