The application of electricity to the annealing of glass bottles and containers

The paper explains the nature and primary importance of annealing processes as applied to commercial glassware, with particular reference to bottles and containers. Development stages, from heated brick arches to portable and continuous lehrs, are described in the section on mechanical improvements. The application of controlled heat to the fused and moulded product is shown through the transition stages of coal, producer-gas and oil firing, to complete electrification of annealing lehrs. Insulation factors and methods; heat conservation and re-application; cooling gradations; economic and product quality considerations in favouring the application of electricity as a power and heating element, are all made subjects for explanatory data. A brief account is given of tumbler-edge glazing and enamelling, which involve the processing of pre-annealed cold ware.