Method and apparatus for tempering glassware

Abstract

Ducts are provided to direct cooling gas onto the outer and interior surfaces of a rotating article of glassware that is heated to a uniform temperature above the strain point of the particular glass composition from which the glassware is formed in order to temper the glassware by producing beneficial residual compressive stresses on the surfaces. The ducts have gas emitting nozzles that shape the cooling gas streams to conform to the shape of the glassware surfaces. The ducts and nozzles are so positioned that the cooling gas impinges upon the glassware surfaces tangentially and in a direction opposite to the direction of rotation of the surfaces to increase the effective velocity of the gas and to promote laminar flow of the cooling gas over the surfaces and thereby enhance cooling. The duct and nozzle that direct gas against the interior surface have a helical baffle plate associated therewith so that the cooling gas is scooped out of the glassware by the baffle plate after it contacts the interior surface and is heated thereby. The cooling gas is preferably compressed air.

Dependencies are inferred from the claim text.