Fusion Quality and Easy Assembly in XL 1. Sliding over Anybody ever having laid large HD-PE pipes and fused large couplers knows the challenges at the construction site. The effects of out-of-roundness, tolerances and local flattenings at the pipe become stronger with increasing dimension. Fusion and cooling times are considerable. From the dimension d 1000mm, the traditional processing with rounding clamps and cylindrical couplers reaches its limits. Often, the pipe must be processed in several steps. In short: How does the oval pipe fit into the round coupler? This is where the principle of the conical ring coupler comes into play. The coupler which flexibly adjusts to the pipe! In combination with the tapered internal contour of the coupler, diameter differences of up to 20mm can be bridged using the conical rings. Thus, an extremely easy assembly after only one single scraping is achieved. The conical rings also facilitate a gap-free fusion and offer an integrated restoration of the pipe's roundness. Fusion only necessitates little energy, the fusion and cooling times are short and fusion results in optimal quality.