Extruder structures

Abstract

Abstract A METALLIC SANDWICH, OR MULTIPLE PLATE ASSEMBLY, IS PROVIDED, FOR APPLICATIONS WHERE STRUCTURAL STRENGTH IS REQUIRED AND AT THE SAME TIME AN EXPOSED SURFACE MUST BE HIGHLY RESISTIVE TO ABRASIVE WEAR, A TYPICAL APPLICATION BEING AN EXTRUDER HEAD FOR THE EXTRUSION OF PLASTICS. FOR SUCH AN EXTRUDER STRUCTURE, HAVING DISCHARGE OPENINGS AT THE EXIT FACE, WHICH FACE IS ADAPTED TO COOPERATE WITH A MOVING CUT-OFF BLADE, AND FOR OTHER SUITABLE APPLICATIONS, THE INVENTION PROVIDES AN ASSEMBLY COMPRISING A SERIES OF AT LEAST THREE PLATE MEANS, ONE OF WHICH IS A PRESSURE PLATE AND ANOTHER OF WHICH IS A WEAR PLATE, BETWEEN WHICH ONE OR MORE ACCOMMODATION PLATES ARE LOCATED, THE PLATES BEING SECURED TOGETHER IN SERIES RELATIONSHIP AND BEING RESPECTIVELY MADE OF MATERIALS HAVING SUCCESSIVELY PROGRESSING DIFFERENT COEFFICIENTS OF THERMAL EXPANSION, AT LEAST UNDER CERTAIN CRITICAL TEMPERATURE CONDITIONS, AND THE PLATES ARE TYPICALLY SECURED TOGETHER BY BRAZING MATERIAL AT THE INTERFACES, THE SAID PROGRESSING DIFFERENT COEFFICIENTS OF THERMAL EXPANSION BEING CHARACTERISTIC OF SAID PLATES AT LEAST AT A TEMPERATURE IN THE NEIGHBORHOOD OF THE FREEZING TEMPERATURE RANGE OF THE BRAZING MATERIAL. THE DISCLOSURE IS INCLUSIVE, INTER ALIA, OF PRESSURE PLATE MEANS OF STAINLESS STEEL, WEAR PLATE MEANS OF TUNGSTEN CARBIDE, AND ACCOMMODATION PLATE MEANS VARIOUSLY EMBODYING TITANIUM, TANTALUM, IRON, NICKEL, COBALT AND CHROMIUM, SOME SEPARATELY AND SOME AS ALLOYS. TO ASSURE A FIRM BRAZED BONDING OF THE SEVERAL PLATE MEANS, IN TYPICAL EMBODIMENTS OF THE INVENTION THE INTERFACES ARE GIVEN A ROUGH FINISH. SUPPLEMENTAL SECURING MEANS SUCH AS THREADED DEVICES MAY ALSO BE EMBEDDED IN THE ASSEMBLY.

Inventors

• 👤 Alfred Wurster
• 👤 Robert C Tanner

Bibliographic Details