Stopper rod having fibrous protective sleeve

Claim 2

In the method of molten metal handling wherein molten metal is discharged from a nozzle set in the base of a vessel by raising a stopper rod therefrom the improvement which comprises providing on the stopper rod a covering sleeve, closely fitted on the end of the rod and contacting the nozzle, the sleeve being formed of a heat-insulating composition which resists thermal disintegration, said sleeve consisting essentially of, by weight, 45 - 94% particulate refractory material, 5 - 50% fibrous refractory material and 1 - 15% by weight binder.

Claim 3

The method of claim 1 wherein the composition of the sleeve includes up to 10% by weight of fibrous organic material.

Claim 4

The method of claim 1 wherein the sleeve is a friction fit over the end of the stopper rod.

Claim 5

In apparatus for handling molten metal which includes a vessel having a molten-metal discharge nozzle and longitudinally movable stopper rod having an inner end disposed in the vessel for opening and closing the inner end of the nozzle, the improvement comprising a refractory, heat-insulating, non-disintegrating sleeve push-fitted over the inner end of the stopper rod so as to be engageable with the nozzle, said sleeve being non-wetted by the molten metal and being constructed essentially of, be weight, 45-94% particulate refractory material and 5-50% fibrous refractory material bonded together with 1-15% by weight binder to form a monolithic body.

Claim 6

In apparatus for handling molten metal which includes a vessel having a molten-metal discharge nozzle and longitudinally movable stopper rod having an inner end disposed in the vessel for opening and closing the inner end of the nozzle, the improvement comprising a refractory, heat-insulating, non-disintegrating sleeve push-fitted over the inner end of the stopper rod so as to be engageable with the nozzle, said sleeve being non-wetted by the molten metal and being constructed essentially of, be weight, 45-94% particulate refractory material and 5-50% fibrous refractory material bonded together with 1-15% by weight binder to form a monolithic body.

Claim 7

Apparatus as in claim 4 wherein the particulate refractory material is selected from the group consisting of silica, alumina, refractory silicates, chamotte, quartz, magnesia, diatomaceous earth and mixtures threof, wherein the fibrous refractory material is selected from the group consisting of asbestos, slag wool, rock wool, glass wool, aluminium silicate fibre, calcium silicate fibre and mixtures thereof, and wherein the binder is selected from the group consisting of colloidal silica sol, colloidal alumina sol, sodium silicate, potassium silicate, fireclay, starches, resins and vinyl-acetate-containing polymers.

Claim 8

Apparatus as in claim 4 wherein said stopper rod is constructed of a central metal rod surrounded by a relatively thick layer of refractory material and wherein said sleeve is substantially thinner than said layer.