Socket Fusion
This is a reliable process as it offers a 100% interference fit, unlike SCH80/40 vinyl products that allow for partial penetration without any need for joining aid. PVDF socket fusion fittings have a thicker wall compared to butt fusion which improves the pressure rating/safety factor of the fittings. Although a socket fusion joint cannot be repeated in case of an error, it allows for precise final dimensions if welding steps are followed as recommended in the manufactures technical catalog.
Typical Applications up to 110mm (4”): Chemical, Pulp & Paper, Mining, Metal Pickling, Power, etc…
Butt Fusion
This is a conventional but still the most common process for joining thermoplastics and recommend for fusing larger-diameter PVDF piping systems. A widely known advantage of the butt fusion process is that it can be repeated by cutting and re-working the joint depending on the final dimensions to achieve. It is an easier process to work with for the operator, as less material has to be heated and displaced to complete the joint. Butt fusion joints can leave a sizeable bead internally that can create turbulence in flow and must be accounted for during design. Welding tool operators are suggested to use long-leg fittings as they may find it difficult to fuse short-leg fittings due to limited room on the welding tool itself.
Typical Application up to 200mm (8”): Chemical, Pulp & Paper, Mining, Metal Pickling, Power, etc…
IR Fusion
This is a relatively newer process but is similar to butt fusion conceptually – two PVDF components walls fused to form a fine bead. This small bead is entirely free of impurities that come from the heated plate. This sophisticated process and specialized tool require rigorous training and maintenance. A standard manual IR tool designed for non-contact fusion can pose some challenges to maintaining enough distance between the heated plate and components which may lead to a cold joint or an internally collapsed ‘flower’ shaped joint. Typical Application up to 200mm (8”): UHPW
All PVDF joints must be executed by a skilled and qualified welder. All steps recommended before and during the process are critical in order to achieve a perfect joint. Simple tasks such as chamfering pipe end before socket fusion and not overlooking changeover time are essential in the case of PVDF. Sangir PVDF joints are tested using the below DVS standards table for each process.
