A screw extruding machine for extruding a material such as rubber, plastics or the like kneaded and blended into a sheet-like form. The screw extruding machine includes two screws horizontally and rotatably supported on a casing, a top-open hopper provided on the side of a screw base portion of the casing, an outlet opened in an axial direction of the screw on the side of a screw front end of the casing, and a roller die in proximity of the outlet, the screw having a feed portion which corresponds to a portion facing the hopper and a compression portion which corresponds to a front end side, whereby material to be extruded supplied from the hopper is extruded into a sheet-like form by the roller die from the outlet via the feed portion and the compression portion by the rotating twin screws, the hopper being positioned over the feed portion of each screw.

According to the present invention, there is provided a spray nozzle assembly for use in a spray drying apparatus, particularly for use in spraying a slurry of sulfur oxide absorbent particulate material into a hot furnace flue gas for removingthe sulfur oxides contained in the flue gas as a dry sulfur-containing salt, wherein the atomizing spray means, whether a spray nozzle or a spinning atomizer wheel, may be withdrawn from the spray nozzle assembly without removing the remainder of thespray nozzle assembly from the spray drying apparatus.

The spray nozzle assembly of the present invention comprises, inter alia, an annular swirler vane assembly disposed about a gas inlet in the roof of the spray dryer apparatus housing and defining an annular flow passageway through which thedrying gas passes from a drying gas supply duct into the spray drying apparatus, an atomizing spray head housing disposed coaxial within the center of the annular swirler vane assembly, an elongated guide tube mated with the atomizing spray head housingand extending upwardly through the drying gas supply duct to terminate externally of the gas supply duct, an atomizing spray head disposed at a central opening in the floor of the atomizing spray head housing with a spray tip extending into the spraydrying apparatus, and a support tube extending upwardly from the atomizing spray head and being slidably translatable within the guide tube so as to permit the support tube and the atomizing spray head attached thereto to be withdrawn upwardly throughthe guide tube and the drying gas supply duct to a location exterior thereof for inspection and maintenance.