The Westlake machine was developed for blowing bulbs for domestic lamps and radio valves at production rates of up to 75,000 a day (gross). It has since been adapted for making drinking glasses, including stemmed ware, at up to 55,000 a day (gross).
The machine copies the action of a handblower in gathering glass from the furnace, forming a parison and blowing the article in a cast iron mould. Twelve pairs of spindles or blowpipes, together with their blowing air valves and past moulds, travel around a central column. The gathering equipment is carried on top of the column and sets of cams are fitted around the column to control the sequence of operations.
Glass is gathered by vacuum into a pair of blank moulds and the pairs of blanks are transferred in turn to each pair of spindles. The spindles are rotated and swung down, and air is introduced to form each blank into a parison, controlling the profile and distribution of the glass before blowing the required shape in the wetted mould.
The mould opens and the spindle jaws release the article that is then transferred to the stemming machine. Here the neck formed in the mould is reheated and stretched to the required length. The article then passes to the burn-off machine where oxygen-gas flames remove the "moil" or waste glass, which was originally formed at the gathering position, and the finished piece is conveyed to the lehr for annealing.
The ribbon machine was developed for the high-speed manufacture of bulbs for domestic lamps, auto lamps, vacuum flasks, etc. Its main feature is that glass travels through it in a straight line rather than on a rotary path as with the Westlake machines. Production rates in excess of 1000 a minute can be achieved.
From the furnace forehearth molten glass flows down between two rotating water-cooled rollers and on to the Ribbon machine. On leaving the rollers the ribbon of glass is carried through the machine on a series of orifice plates, forming a continuous belt pierced with holes.
As the ribbon moves forward, a continuous chain of blowheads does the glassblower’s job for him. It blows the glass through the hole and the "blister" forms into a bulb inside a rotating mould, which meets and closes around it from below. Still moving forward on the ribbon, the shaped bulb is released from its mould, cooled by air jets and then tapped off the ribbon to fall onto the scoops of a rotary turntable which tips it onto a conveyor belt. This carries it through an annealing lehr and air cooling to inspection and packing. The unused part of the ribbon passes direct to a cullet system for re-melting. More than 1,000 bulbs per minute can be produced on such a machine.