Patent GB-312887-A (GB)
Title: Method of and apparatus for feeding glass
IPC: C03B7/10
Filed: 1928-10-18
Abstract: 312,887. Miller, W. J. Oct. 18, 1928. Delivering molten metal.-A device for feeding charges of molten glass comprises a tubular conduit extending vertically from the outlet of a forehearth to a height just above the normal level of the glass, an annular wall surrounding the conduit, and a cylindrical plunger or impeller which telescopes into the space between the conduit and the wall and is reciprocated to cause a pulsating flow of glass from the forehearth through the conduit and thence through the outlet. The apparatus comprises a forehearth 11, Fig. 1. having an aperture in its floor into which the outlet member is fitted. This member consists of an outer cylindrical shell 5, a tubular member 6 concentric with the shell, and a bottom 4. The inner member 6 extends a little above the normal level of the surface of the glass in the forehearth, and its lower end is open and forms the outlet aperture 20. The plug or impeller 15 has a hollow extension which telescopes into the space between the members 5, 6 and its diameter is such that the space 18, between the extension 17 and the shell 5, is narrower than the space 19 between the extension and the inner member. The impeller is reciprocated vertically and on its downstroke causes the glass to flow through the member 6 and through the outlet 20. On its upstroke, the flow of glass is arrested and a neck n is formed which is cut through by shears 21. If the impeller is withdrawn from the glass, the flow through the tube 6 ceases. The body 15 of the impeller may be solid, as shown, or it may be formed with an axial bore through which suction and compression may be applied to the space within the extension 17 to assist in feeding the glass. The alternating pressures may also be used without reciprocation of the impeller. If desired, the impeller may be rotated to stir the glass. Two or more sets of apparatus may be installed in a single forehearth, or two apertures may be formed at the lower end of the tube 6. Fig. 16 shows a construction in which the impeller is rotated and is connected with devices for applying suction and compression to the extruding glass. The impeller 15 is connected by pins 26 with a head 27 which has a downwardly extending cylindrical shell 28, immersed in a bath 29 containing fluid for making an air-tight and heat-confining seal. The shell also forms a sliding fit over an inner shell 97 and thus guides the impeller 15 in its vertical movement. The head 27 is also provided with a ring 30 which is engaged by a lever 31 pivoted to a standard 35. The free end of the lever carries a roller 39 which runs on a cam 40 secured to a vertical shaft 41, so that rotation of the shaft causes reciprocation of the impeller. The shaft also carries a wide pinion 42 which engages a spur wheel 43, secured to the head 27, and thus rotates the impeller. An axial bore 47 in the impeller is connected by a pipe 49 with valves 54 operated by cams 55, 56 on the shaft 41. These valves are connected with a supply of compressed air and a vacuum tank, and the rotation of the shaft causes the alternate application of suction and compressed air to the space within the impeller extension. Another cam 58 on the shaft 41 operates the shears 21, and other cams 62, 63 operate a receiving cup 60. This cup, carried by an arm 61, is brought beneath the aperture 20 and shapes the end of the emerging glass. Before the glass is cut by the shears, the cup is lowered and swung to one side to allow the severed charge of glass to fall into a mould 65. Instead of being rotated continuously, the impeller may be rotated intermittently with periods of rest.