Apparatus for making thin ceramic plates

Claim 1

APPARATUS FOR MAKING THIN FLAT CERAMIC PLATES HAVING A THICKNESS WHEN FIRED OF THE ORDER OF 10 MILS, COMPRISING AN EXTRUDER FOR THE PLASTIC CERAMIC MIX HAVING A DIE WITH AN EXTRUDING ORIFICE HAVING A WIDTH AND THICKNESS EQUAL TO THE CORRESPONDING DIMENSIONS OF THE FIRED PLATE PLUS THE FIRING SHRINKAGE, SAID ORIFICE HAVING UPPER AND LOWER SIDES DEFINING THE THICKNESS AND ENDS DEFINING THE WIDTH, SAID DIE HAVING A THROAT UPSTREAM WIDER AND THICKER THAN THE ORIFICE AND TAPERING DOWN IN CROSS-SECTIONAL AREA TOWARD THE ORIFICE, THE RATE OF TAPER OF THE THROAT OPPOSITE THE CENTER OF THE ORIFICE BEING INITIALLY FASTER THAN THAT REQUIRED TO MEET THE UPPER AND LOWER SIDES OF THE ORIFICE AND THEREAFTER SMOOTHLY MERGING INTO SUCH SIDES AND PROVIDING A FRICTION INCREASING RESTRICTION IN THE THROAT OPPOSITE THE CENTER, THE RATE TO TAPER OF THE THROAT OPPOSITE THE ENDS OF THE ORIFICE BETWEEN THE UPPER AND LOWER SIDES MOST REMOTE FROM THE CENTER OF THE ORIFICE BEING INTIALLY SLOWER THAN THAT REQUIRED TO MEET THE UPPER AND LOWER SIDES AND ENDS OF THE ORIFICE WHEREBY THE THROAT REMAINS WIDER AND THICKER THAN THE ORIFICE UNTIL JUST BEHIND THE ORIFICE AND THEREAFTER SMOOTHLY MERGING INTO SUCH ENDS BY FILLETS CONNECTING THE THROAT TO THE UPPER AND LOWER SIDES AND ENDS OF THE ORIFICE AT THE CORNERS WHERE THE SIDES AND ENDS MEET AND PROVIDING A FRICTION RELIEVING SECTION IN THE THROAT OPPOSITE PORTIONS OF THE THE RATE OF TAPER OF THE THROAT OPPOSITE PORTIONS OF THE ORIFICE BEING INTERMEDIATE THAT AT THE CENTER AND ENDS, THE TAPER OF THE THROAT ON EACH SIDE OF THE CENTER BUT LESS REMOTE THAN THE ENDS BEING ADJUSTED SO THE FRICTION IN THE THROAT UPSTREAM OF THE ORIFICE PLUS THE FRICTION IN THE ORIFICE IS CONSTANT ACROSS THE WIDTH OF THE ORIFICE AND ALL PARTICLES EXTRUDED THROUGH THE ORIFICE TRAVEL AT SUBSTANTIALLY THE SAME SPEED.