公开(公告)号：US3711267A

公开(公告)日：1973-01-16

申请号：US3711267D

申请日：1971-07-26

Applicant: EMHART CORP

Inventor： FENTZKE A

IPC: C03B7/086 ,  C03B11/06

CPC classification number: C03B7/086

Abstract: A FEEDER BOWL IS MOUNTED AT THE END OF A MOLTEN GLASS FOREHEARTH, AND HAS A RECIPROCATING PLUNGER AND ROTATING TUBE FOR FEEDING GOBS OF THE MOLTEN GLAS THROUGH AN ORIFICE IN THE OUTLET SPOUT OF THE FEEDER BOWL. TO COMBAT THE TENDENCY FOR THE PLUNGER TO ACT AS AN ELECTRODE IN A GALVANIC CELL CREATED IN THE MOLTEN GLASS THE PLUNGER IS MADE UP FROM TWO REFRACTORY MATERIALS, ONE FOR USE IN THE GLASS, STHE OTHER FOR USE ABOVE THE GLASS SURFACE TO ELECTRICALLY INSULATE THE SUBMERGED PORTION FROM THE METALLIC PLUNGER OPERATING MECHANISM. A METHOD IS DISCLOSED FOR FORMING THE COMPOSITE REFRACTORY PLUNGER IN THREE ZONES, THE UPPER AND LOWER ZONES BEING DISTINCT MATERIALS, AND THE THIRD ZONE BEING FORMED INTEGRALLY WITH THE OTHER TWO AS A TRANSITION ZONE COMPRISING A MIX OF THE TWO REFRACTORY SLIP COMPOSITIONS INTRODUCED THROUGH A SERIES OF BIFURCTED METERING VALUES IN THE HOSES OR PIPES NORMALLY USED IN THE SLIP CASTING PROCESS. THE UPPER ZONE COMPRISES APPROXIMATELY 90% BY WEIGHT OF ALUMINA, AND THE LOWER

ZONE LESS THAN 80% BY WEIGHT OF THIS MATERIAL. ZIRCONIA IS PRESENT TO THE EXTENT OF LESS THAN 2% BY WEIGHT IN THE UPPER ZONE, AND COMPRISES APPROXIMATELY 10%-15% BY WEIGHT OF THE COMPOSITION OF THE LOWER ZONE. THE TRANSITION ZONE COMPRISES A SUBSTANTIAL PERCENTAGE OF ALUMINA AND SOME SILICA IS PRESENT IN ALL THREE ZONES.