The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 14, 1989
Filed:
May. 20, 1987
Wilfried Venzke, Moglingen, DE;
Werner & Pfeiderer GmbH, , DE;
Abstract
In a method of operating a screw extruder having a drive motor in which the speed of rotation of the drive motor is controlled, in order to achieve as constant a quality of product as possible, the speed of rotation is controlled depending on the specific energy input in such a manner that the specific energy input is maintained substantially constant. A control depending on the product temperature may advantageously be superimposed on the control keeping the specific energy constant in the form of a cascade control. A screw extruder for carrying out the method has a housing in which a screw is mounted, a drive motor having a variable speed for continuously driving the screw, feed devices for supplying basic products, additives and the like, and a control device for controlling the speed of rotation of the screw. The drive motor is controlled by a device for measuring the driving power of the drive motor and a device for determining the product throughput, a signal corresponding to the quotient of driving power and throughput being fed as an actual value to the control device which has an output connected to the drive motor in order to maintain the specific energy input constant.