Abstract: An extrusion head for blow molding extruded plastic containers, with a ring gap nozzle having a mandrel and a ring-shaped nozzle body having an elastically deformable sleeve, and setting devices for radially deforming the elastic sleeve. The sleeve defines a nozzle gap, the width of which is variable by axially movement of the mandrel and/or of the nozzle body. The geometry of the gap can be changed by deforming the sleeve in the course of extrusion of a hose-like, pre-shaped blank. The sleeve is axially supported in the nozzle body, and/or on the mandrel only on segment-like surfaces.

Abstract: A process for blow-molding hollow bodies from thermoplastic synthetic resin wherein, in addition to control to accurately position an extruder thermoplastic melt preform in the blow mold and to maintain a constant weight of the extruded preform, on the program curve which itself is a superimposition of the profile curve of the preform and a base gap determined in accordance with the nozzle gap width through which the preform is extruded, there is superimposed a correction strip which can be varied depending upon material distribution changes as a result, for example, of sag of the preform.