oa New Stirrer Technology for the Glass Industry

The function of stirring in glass making is to create uniform, homogeneous glass. Stirring equipment operates at high temperatures and under high mechanical stresses, so stirring devices have to be robust and often involve large amounts of platinum or platinum alloys. The stirrers, stirrer bars, blenders, homogenisers, screw plungers and plunging stirrers currently used are generally effective in operation, reliable and with predictable lifetimes. Thus there has been no incentive to improve the technology, and stirrer designs have changed little in the last twenty or thirty years. However, the current economic climate in the glass industry demands lower costs, improved operational efficiency, and reduced platinum inventories – glass making uses large quantities of platinum, with stirring devices taking a large part of it. To help reduce these amounts work has been undertaken on stirrer technology. and recent developments have resulted in lower platinum requirements (in some cases by over 90 per cent) without jeopardising stirring effectiveness or stirrer longevity. Different types of glass stirrers are examined here and a new concept in stirrer design, a ‘diffusion choke’, is described.