Method of thermal toughening of glass in a fluidized bed
AssigneePilkington Brothers Limited
InventorsRaymond P. Cross, Gordon T. Simpkin
Life of this patent
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Abstract
Glass is heated to a temperature above its strain point and is thermally toughened by chilling with a quiescent gas-filuidized particulate material which has gas-generating properties and a mean particle size in the range 30 .mu.m to 120 .mu.m, a particle size distribution in the range 1.15 to 2.78, a flowability in the range 69.5 to 92, and a thermal capacity per unit volume at minimum fluidization in the range 0.7 to 1.59 MJ/m.sup.3 K. The invention is particularly suitable for thermally toughening glass sheets for vehicle windscreens.
Claims5
A method of thermally toughening glass comprising heating the glass to a temperature above its strain point and chilling the hot glass with a gas-fluidised particulate material in a quiescent uniformly expanded state of particulate fluidisation, wherein the particulate material is aluminium trihydrate (Al.sub.2 O.sub.3.3H.sub.2 O) having a mean particle size in the range 62 to 86 .mu.m, a particle size distribution in the range 1.64 to 2.73, a flowability point score in the range 69.5 to 82, and a thermal capacity per unit volume at minimum fluidisation in the range 1.52 to 1.59 MJ/m.sup.3 K.
A method of thermally toughening glass comprising heating the glass to a temperature above its strain point and chilling the hot glass with a gas-fluidised particulate material in a quiescent uniformly expanded state of particulate fluidisation, wherein the particulate material is aluminium monohydrate (Al.sub.2 O.sub.3.1H.sub.2 O) having a mean particle size in the range 45 to 57 .mu.m, a particle size distribution in the range 1.15 to 2.78, a flowability point score in the range 74 to 80, and a thermal capacity per unit volume at minimum fluidisation in the range 1.16 to 1.18 MJ/m.sup.3 K.
A method of thermally toughening glass comprising heating the glass to a temperature above its strain point and chilling the hot glass with a gas-fluidised particulate material in a quiescent uniformly expanded state of particulate fluidisation, wherein the particulate material is magnesium hydroxide containing combined water of crystallisation.
A method of thermally toughening glass comprising heating the glass to a temperature above its strain point, and chilling the hot glass with a gas-fluidised particulate material in a quiescent uniformly expanded state of particulate fluidisation, wherein the particulate material is a hydrated iron oxide (FeO.OH) containing combined water of crystallisation having a mean particle size in the range 30 .mu.m to 120 .mu.m, a particle size distribution in the range 1.15 to 2.78, a flowability point score in the range 69.5 to 92, and thermal capacity per unit volume at minimum fluidisation in the range 0.7 to 1.59 MJ/m.sup.3 K.
A method of thermally toughening glass comprising heating the glass to a temperature above its strain point, and chilling the hot glass with a gas-fluidised particulate material in a quiescent uniformly expanded state of particulate fluidisation, wherein the particulate material is magnesium hydroxide containing combined water of crystallisation having a mean particle size in the range 30 .mu.m to 120 .mu.m, a particle size distribution in the range 1.15 to 2.78, a flowability point score in the range 69.5 to 92, and thermal capacity per unit volume at minimum fluidisation in the range 0.7 to 1.59 MJ/m.sup.3 K.
Dependencies are inferred from the claim text.