Glass products

Modern glass container factories are broadly divided into three parts: the batch house, the hot end and the cold end. The batch house is concerned with raw materials. In the hot end are furnaces, machines that produce the containers (forming machines) and annealing ovens. In the cold end there are the inspection and packaging equipment.
The batch house holds the raw materials for glass, primarily sand, soda ash, limestone, feldspar (as well as others). These materials are received (typically by truck or rail transport) and elevated into storage silos. From the silos they are weighed out into a batch of several tonnes, using common glass batch calculation procedures. The batch is mixed and sent to silos over the furnace.
The hot end of a glassworks is where the molten glass is formed into containers, beginning when the batch is fed at a slow controlled rate into the furnace. The furnaces are natural gas or fuel oil fired and operate at temperatures up to 1675°C.The temperature is only limited by the quality of the furnace superstructure material and by the glass composition.
There are currently two primary methods of making a glass container - the blow and blow method and the press and blow method. In all cases a stream of molten glass at its plastic temperature (1050°C-1200°C) is cut by a shearing blade to form a cylinder of glass called a gob. Both of the processes start with this gob falling by gravity and guided by troughs and chutes into the blank moulds. In the blow and blow process, the glass first is blown from below into the blank moulds to create a parison or pre-container. This parison is then flipped over into a final mould, where a final blow blows the glass out in to the mould to make the final container shape. In the case of press and blow, the parison is formed by a metal plunger which pushes the glass out into the blank mould. The process then continues as before, with the parison being transferred to the mould, and the glass being blown out into the mould.