The new generation of the STS expander roller: Type D
The outstanding feature of the Type D expander roller is the following fundamental modification:
Width expansion is concentrated at the peripheral areas of the fabric.
Ground shape and profiling were modified so as to enable an improved smoothing of the critical outer sections of the fabric web. Profiling is required only in partial areas of the roller, a feature which is also cost-saving.
Nevertheless, the entire fabric is expanded and smoothened, respectively. In this respect, the Type D roller comes closer to the idea of contactless width expansion desired by engineers, since every contact involves the danger that the fabric web will be damaged or marked. As a result, the expansion/smoothing process is more gentle on the fabric web.
Due to partial profiling, it is not required any more that the fabric runs over a completely profiled surface at the start of machine operation, thereby further minimising the risk that in particular very thin and delicate fabric is drawn into the helix.