Abstract: An injection nozzle for installation in the wall of a vessel for introducing gas into a liquid in the vessel. The nozzle comprises a body pierced by a passage which is terminated at the discharge end of the nozzle by a gas-porous or foraminous passage-closing means. Means is provided gas-tightly affixed to the closing means to feed gas thereto. The gas-feeding means includes a duct structure which extends along the passage between the closing means and the inlet end of the body. The duct structure provides a substantially leak-tight gas-feed path from an external gas delivery means to the passage-closing means. The duct structure can be adjustable or extensible in length.

Abstract: For injecting gas into a liquid, more particularly a molten metal, a nozzle body (24) is installed in the wall of a liquid containment vessel, the body (24) having a nozzle passage (25) therethrough. Liquid and gas tightly fitted in a downstream end of the passage is solid, gas porous plug (18) having capillary gas passage (20). Upstream of the plug (18) the passage has a gas-porous and liquid-impermeable cartridge (10) closely fitted therein which prevents liquid which may conceivably pass through the plug (18) from leaking out of the passage (25). The cartridge (10) has a gas impermeable metal sleeve (11) containing a particulate material (16) such as sand which is retained in the sleeve (11) by wads (14, 15) of fibrous material at the ends of the sleeve.