GB355555A - Improvements in forehearths for glass melting furnaces - Google Patents

Abstract

355,555. Glass manufacture. JACKSON, L. MELLERSH-, 28, Southampton Buildings, London.-(Hartford-Empire Co. ; 333, Homestead Avenue, Hartford, Connecticut, U.S.A.) Sept.27,1930, No. 29021. [Class 56.] Delivering molten metal.-The molten glass in the channel of the forehearth of a glass melting furnace is maintained at substantially uniform fluidity by providing a central longitudinal opening in its roof to permit radiation of heat from the centre of the channel and long narrow flames directed downwardly on to the glass adjacent the side walls of the channel. In the construction shown in Figs. 1 and 2 the upper forehearth structure above the channel 1 includes transverse refractory walls 16, 52 and a middle refractory partition 15 dividing the structure in a rear chamber 24 and a front chamber 49. The chamber 24 is bridged by pairs of hinged refractory shutters carried by holders 32 supported by fulcrum rods 35. Each pair of shutters 25 may be rocked independently of the other pairs to vary the heat radiation by chains 38, 39 attached to wheels 40 rotated by handles 42. When closed a space 36 between the ends of the shutters permits the escape of hot gases. Firing chamber 26 extending along the side walls 18 of the chamber 24 are fitted with burners 47, the flames from which pass through slots 21a in supporting blocks 21 and are deflected by lips 18a on the walls 18 on to the side portions of the glass in the channel. The front chamber 49 is provided with two side combustion chambers 51 each having its rear wall composed of refractory blocks, to which is secured a plate 66 carrying a gaseous or liquid fuel burner provided with two series of annular air ports. The delivery end of the forehearth comprises a feed bowl 7 insulated by granular material 9 and fitted with a reciprocating member surrounded by an adjustable rotating tube 13. The front of the forehearth is provided with stacks 81, 82 fitted with adjustable dampers 83, 89. The temperature of the glass may be indicated and controlled by thermo couples 90. Fig. 6 shows another construction of forehearth in which hinged shutters 102 .. 105 pivoted on spindles 106 over openings above the longitudinal channel 100 are opened in turn by the engagement of blocks 119 .. 122 on a slidable rack bar 112 with rocker arms 108 .. 111 on the spindles 106. The rack-bar 112 is operated through reduction gearing by a reversible electric motor 118 controlled by a thermo-couple 130. The fore-hearth may be used with either a feeder or suction gathering machine.