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:
Sep. 12, 1989
Filed:
Apr. 14, 1988
Gunther Becker, Geretried, DE;
Gerhard Reisinger, Egling, DE;
Peter Taubenmann, Munich, DE;
Norbert Lisker, Wolfratshausen, DE;
Elastogran Polyurethane GmbH, Lemforde, DE;
Abstract
A method and apparatus for metering and mixing multi-component plastics, in particular polyurethane, in which two or more hydraulic piston and cylinder units (A.sub.1 and A.sub.2) for each component, operate periodically by a balanced procedure. The pressure for the second piston and cylinder unit which takes over metering is equilibrated, before the beginning of the metering procedure, with the pressure of the first piston and cylinder unit which is in the process of metering. Switching from one piston and cylinder unit to the other (e.g. from A.sub.1 to A.sub.2) takes place in such a way that metering is taken over by the second piston and cylinder units at the same time as the first piston and cylinder unit is switched off. This is achieved by providing a pilot valve which has zero overlap and inevitably releases the component stream from the first piston and cylinder unit at the same time as the other piston and cylinder unit is switched off. Pressurization and pressure equilibration are effected by a hydraulic control apparatus which is incorporated in the hydraulic loop of the volume stream and automatically equilibrates the initial pressure with the metering pressure. This permits pressurization and pressure equilibration without additional parts in the component system.