NATURAL BENDS IN PEXGOL PIPES
When designing and installing Pexgol pipes in natural bends, high bending moments might be exerted upon the end- connectors. In case of self- restrained fittings no special care should be taken.
In case of non-restrained fittings to special care should be taken to prevent excessive bending moment on the end-connectors due to forced installation.
See “Non-Restrained Fittings and Pullout Prevention Techniques”.
Bending the Pipes
Use a suitable device, such as a winch or a lever, to bend the pipes. Remember that the pipe is rigid and considerable force is required for bending and fixing it – for example,
2 metric tons for a 4” pipe and 5 metric tons for a 10” pipe.
Please exercise caution!
Bend the pipe carefully to avoid kinking. For best results, it is recommended to prepare a continuous support (with the radius of the pipe to be bent) for the pipe. Then bend the pipe against it.
The installation is complicated since it is difficult to calculate in advance the exact length of the pipe. As a result, on-site adaptation (field welding) is necessary.
Proper Installation Procedure
1. The longer arm of the natural bend is more flexible than the shorter arm; therefore, always choose the longer arm as the pipe end whose length is adjusted.
2. Install the fitting onto the end of the shorter arm.
3. Connect the shorter arm to the existing counter- flange.
4. If necessary, install a fixpoint clamp before the fitting to protect it during bending.
4.1 If the fitting is an electrofusion fitting, wait three cooling times (3x) before continuing with the next step.
5. Adjust the length of the longer arm.
6. Cut the length and install the fitting.
6.1 If the fitting is an electrofusion fitting with a stub-end Bending the Pipes Proper installation procedure: Natural Bends in Pexgol Pipes (flared end) connection, perform the welding when the flared end is free (not connected to the counter-flange). Connect the flared end & flange to the counter-flange only after waiting three cooling times (3x).
6.2. If the fitting is an electrofusion fitting which connects the longer arm to another Pexgol or PE pipe, install a temporary fixpoint bridge before welding in order to protect the electrofusion fitting during welding. Disassemble the temporary fixpoint bridge only after waiting three cooling times (3x).
6.3. See “Non-restrained fittings”.
