Tempering bent glass sheets

An apparatus for tempering a bent glass sheet is disclosed. The apparatus comprises means for conveying the sheet through the apparatus and a pair of blastheads for quenching the sheet with quench gas. Each blasthead comprises a plurality of spaced elongate plenums for supplying quench gas to an array of quench nozzles, the nozzles being mutually inclined to provide diverging jets of quench gas. The plenums extend transversely to the direction of conveyance of the sheet, and the array of nozzles is curved in at least one direction. The array may comprise rows of nozzles extending along lines which are curved in the direction of elongation of the plenums; preferably the curvature of the rows matches the average local curvature of the bent glass sheet in the corresponding direction. Also disclosed is a production line incorporating the apparatus.