Windmoller Holscher

Windmoeller and Hoelscher

Werner Feistkorn

Klemens Sensen

Hans-Udo Beckmann

Klaus-Peter Voss

Richard Saatkamp

Christof Herschbach

Klaus P Vob

To prevent socalled fish eyes or to reduce the number of fish eyes per unit of area in plastic films, manufactured according to the casting process or according to the blown film process, the number of fish eyes per unit of area is measured in the tubular film, which is cast or blown or collapsed. When the measurement reveals a number of fish eyes per unit of area that exceed a specified value, nitrogen or antioxidants are blown or put into the hopper until the number of fish eyes per unit of area falls below a critical number.

Process for the prevention of socalled fish eyes in plastic films

A procedure for feeding plastic granulate into the intake opening of a plastic extruder with a storage tank, and with an intermediate storage tank resting on a weighing device. In the procedure, the specified quantity by weight of material processed for the particular batch is determined by the rotations of the extruder screw In order to specify a procedure in which the recipe-, or batch-, change times is considerably shortened and plastic granulate is conserved, it is provided that the intermediate storage tank is filled through opening of the storage tank discharge with a specific quantity by weight of plastic granulate, and the storage tank is filled with its constant fill quantity after re-closure of its discharge, when the sum of the weight of the fill of both storage tanks corresponds to the remaining quantity by weight to be processed by the extruder, and that the conveyance of plastic material into the storage tank is discontinued, and the storage tank discharge is opened one or more times, until she quantity stored in it has entered into the intermediate storage tank.

Procedure for feeding plastic granulate into the intake opening of a

The invention refers to a method for the reduction of the sag and/or of the different stress profile of a flattened tubular film web produced by a blown film process and made of thermo-plastic synthetic resin, transversely to its longitudinal direction. For the solution of the problem to provide a method according to which the sag and/or the different states of tension transversely to the tubular film web can be easily reduced or eliminated to a maximum degree, the tubular film web is heated along its width and then cooled and/or stretched. Furthermore, the invention refers to an apparatus for carrying out the method.

Method and apparatus for the reduction of the sag and/or of the varying

This invention refers to an apparatus for determining the sag of a running web of material transversely to its longitudinal direction. For this purpose according to the invention a carrier of a web sensing roller is guided in a housing to be movable against spring force transversely to its rotational axis and apparatus is provided for measuring the displacement distance of the roller. The roller is replicated in triplicate across the width of the web. In other embodiments web sag is measured by roller rotation and by web force respectively on the three rollers.

Apparatus for determining the sag of a running web of material

To determine and/or automatically control the degree of orientation of tubular films which have been made in a film-blowing plant including an extruder having a film-blowing head and apparatus for internal cooling and also including flattening and take-off apparatus, the rate of exchange of the air for internal cooling, the speed of the extruder, the temperature of the plastic composition being extruded and/or the take-off velocity are controlled. To ensure that the degree of orientation can be determined and/or automatically controlled in a simple manner and without an occurrence of trouble, that shape of the flaring portion of the bubble which corresponds to the desired degree of orientation is determined and/or adjusted and is recorded as the desired shape of the bubble. The actual shape of the flaring portion of the bubble is detected and compared with and adapted to the desired shape.

Process for controlling the degree of orientation of tubular films

For measuring thickness of films of synthetic thermoplastic which have been solidified but not yet fully cooled after extrusion, a capacitive measuring head is moved into contact with the film and during a measuring cycle is moved over the surface of the film in the area in which the measurement is to be effected. The measuring head is disengaged from the film after each measuring cycle. To ensure that the measurement will not be affected by a temperature rise of the measuring head during a measuring cycle, the measuring head is moved into contact with the film before the measuring cycle begins and the measuring cycle is not initiated until a time has elapsed in which the measuring head has assumed a temperature which remains substantially constant throughout the measuring cycle.

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Saerbeck, Germany

Werner Feistkorn