Davis-standard Corporation

Saulius Tomas Eiva

John P Christiano

Chad Allen Biron

Joseph A Wnuk

Alexandre MacGregor

Christopher Rosivach

Tyler Robert McKenna

A tube forming apparatus for forming polymeric tubing includes a housing between rear and discharge ends. The tube forming apparatus includes a core tube assembly with an exterior core tube and an inner core tube positioned partially therein and in an interior area of the housing. The tube forming apparatus includes a die that has an inner die-surface. A diverter tip is mounted in and extends from the inner core tube into the die forming a die opening between the die and the diverter tip. The tube forming apparatus includes a core tube adjustment system mounted proximate the rear end which includes an axial displacement device configured to axially position the core tube assembly for modulating wall thickness of the tube and/or an angular displacement device configured to modulate the inner core tube for modulating concentricity of the tube.

Polymeric tube forming apparatus with a multi-dimensional control system

The invention is a method for operating an extruder temperature controller. The method can include sensing an actual screw speed for an extruder screw in an extruder barrel. The extruder barrel has at least one heat exchange means. The method can then involve indexing and storing a plurality of screw speeds. Each of the stored screw speeds corresponds to a temperature reset value. Comparing the actual screw speed with each of the stored screw speeds can then be performed. Selecting one of the stored screw speeds can then occur. The selected screw speed is a member of the plurality of stored screw speeds having a value most arithmetically equivalent to the actual screw speed. The step of selecting retrieves the temperature reset value corresponding to the selected, stored screw speed. Generating a control output driver signal to the heat exchange means can occur. The control output driver signal is responsive to the retrieved temperature reset value. The invention includes delaying a control alarm for a predetermined time when generating a control output driver signal to the heat exchange means is at or near maximum capacity.

Method for operating extruder temperature controller with stable temperature reset

The invention is an extruder temperature controller for an extruder barrel. The extruder temperature controller includes means for determining an actual screw speed and has means for storing a plurality of screw speeds. Each member of the plurality of stored screw speeds has a corresponding stored temperature reset value. The extruder temperature controller has a means for comparing and selecting that compares the actual screw speed to each of the plurality of stored screw speeds and selectes a default screw speed. The default screw speed has a smaller deviation from the actual screw speed than any other member of the compared, stored screw speeds. The controller further includes a means for generating a control output driver signal to the heat exchange means. The control output driver signal is the corresponding stored temperature reset value for the default screw speed. The invention further includes a means for delaying a control alarm for a predetermined time when the means for generating a control output driver signal to the heat exchange means operates at or near maximum capacity. The invention includes a method for controlling the temperature of an extruder barrel.

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Ashaway, RI, United States of America

Saulius Tomas Eiva