GB1027302A - Improvements in or relating to apparatus for annealing flat glass - Google Patents

Abstract

<PICT:1027302/C1/1> An annealing lehr for annealing glass advanced therethrough includes, at least in the annealing zone, multiple assemblies each consisting of a series of heat reflecting partitions assembled in spaced relation so that the heat exchange between the partitions is mainly by radiation to give desired thermal insulation at the upper end of the annealing range so that the glass is cooled slowly through the annealing range. Glass ribbon 2 drawn between rollers 4 is passed into an annealing lehr 1 on rollers 3 and initially will be at a temperature above the temperature of the annealing range. Each wall of the lehr 1 includes multiple wall assemblies 7, 8 consisting of parallel heat reflecting partitions 9 to 12 and 13 to 16 held in spaced relation by refractory spacers 17 carried by rigid frames 18, 19 mechanically secured to the refractory walls of the lehr. The sheets 9 to 12 are respectively of a heat resisting steel, a stainless steel and two of aluminium and the sheets 13 to 16, two of stainless steel and two of aluminium, each assembly 7, 8 acting to reduce the heat loss when the temperature of the glass 2 is near the top of the annealing range. Auxiliary heating means 20 may also slow down the rate of heat loss. The assemblies 7 and 8 may be positioned inside the walls of the lehr instead of forming part of the walls. Special arrangements of the partitions 9 to 12 and 13 to 16 may effect differential cooling between the centre portion and the marginal portions of the glass ribbon 2.