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:
May. 20, 1997
Filed:
Dec. 12, 1995
David E Boring, East Berlin, PA (US);
Sonoco Products Company, Hartsville, SC (US);
Abstract
A method and apparatus for extruding thermoplastic tubing of reduced eccentricity, in which tubing is extruded into a vacuum calibration box containing a cooling fluid and a sizing collar. An ultrasonic device for measuring wall thicknesses around the periphery of the tubing is located downstream of the sizing collar. The wall measurements are used to determine a critical parameter, and if this critical parameter is outside of a predetermined range, the vacuum calibration box is moved in the direction of greater wall thickness. After a delay which allows the product of the correction to reach the ultrasonic device, the box is again moved if necessary, until the critical parameter is within the predetermined range.