Patent GB-359489-A (GB)
IPC: C03B7/00
Filed: 1930-07-18
Abstract: 359,489. Glass manufacture. HARTFORD-EMPIRE CO., 333, Homestead Avenue, Hartford, Connecticut, U.S.A.- (Assignees of Peiler, K. E. ; 16, Fernwood Road, West Hartford, Connecticut, U.S.A.) July 18, 1930, No. 21807. Convention date, Aug. 21, 1929. [Class 56.] Delivering molten metal.-A forehearth for a glass furnace, particularly intended for use with a suction-gathering machine, comprises a glassconditioning chamber, a gathering-bay providing an exposed pool of glass, means for sealing the conditioning chamber against heat from the furnace, and temperature-controlling means within the chamber adapted to regulate the temperature and viscosity of the glass in the chamber and in the bay. The forehearth, as shown in Figs. 1 and 2, extends outwards from a tank furnace 11 and comprises a communication section 18, a conditioning section 19, and open gathering-bay 20. The walls of the section 19 diverge between the sections 18, 20, as shown in Fig. 2, and the floor of the bay may slope upwards in order to provide clearance for parts of the forming machine. A skimming and sealing block 21, fitted in the section 18, dips into the glass and is sealed by a luting of suitable material in order to isolate the rest of the forehearth from the tank. The basin of the sections 19, 20 is enclosed in insulating material 27, but any desired portion of the section 18 may be left uninsulated in order to provide for a reduction in the temperature of the glass as it enters the forehearth. An arched roof and a curtain wall 25 enclose the forehearth, and the space above the glass in the section 19 is heated by the flames from burners 47 projected through ports 48. The burnt gases escape through a stack 51 fitted with an adjustable damper 52, and the regulation of this damper and of the burners enables the temperature of the glass in the section 19 to be controlled. The curtain wall 25 is composed of a series of refractory blocks 35, Figs. 1 and 3, which are suspended by screwed rods 36 from a bearing bar 37. This bar is suspended by a pair of screwed rods 39 which pass through holes in brackets 40 and screw into the hubs of worm wheels 42 rotatable by a shaft 44. Thus the curtain wall can be raised or lowered as a whole, and the blocks 36 can be raised or lowered independently of one another by means of nuts 38 on the rods 36. By moving the wall vertically, the gap between its lower end and the surface of the glass can be varied. This enables the radiation from the space enclosed within the wall to the glass in the gathering-bay to be adjusted, and it also permits the adjustment of the draught under the wall. The gathering area of the bay 20 has a cover 46 of refractory material which shields the glass in the bay and minimizes the loss of heat by radiation. The circulation of glass between the section 19 and the bay 20 is caused by the movement through the glass of the moulds of the forming machine, but any suitable mechanical device, such as that described in Specification 310,469, may be used for inducing a circulation in the required direction. A number of these forehearths may be fitted to one tank, and the temperature of the glass in each of them may be regulated as desired to suit the associated forming-machine. Specifications 227,078, 227,079, [both in Class 56, Glass], and 340,110 are referred to.