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:
Apr. 21, 1992
Filed:
May. 31, 1990
Heinz Klein, Pattensen, DE;
Paul Troester Maschinenfabrik, Hannover, DE;
Abstract
A seal on a drive shaft of an extrusion machine having a housing, is provided by a sealing chamber through which the shaft, for example the drive shaft of the shear spindle, extends in entering the housing, and a sealing screw thread on a portion of the shaft in the sealing chamber, the sealing screw thread having a screw direction for propelling material toward the interior of the housing. Sealing material in the form of granular plastic material is fed to the sealing chamber at a controlled rate by a device having a storage container for the granular plastic material, the bottom of the container having a funnel feeding the granular plastic material into an elongate cavity which communicates with the sealing chamber and in which the piston rod of a piston-cylinder unit is reciprocable to propel the granular plastic material into the sealing chamber. The pressure inside the sealing chamber is sensed and the operation of the piston-cylinder unit is controlled to maintain the pressure approximately constant. Fluid is circulated in a channel in the wall of the sealing chamber to keep the temperature of the chamber below the melting temperature of the granular plastic material.