Nozzle for use in rotational casting apparatus

Abstract

For use in a rotational casting machine used for coating a rotating body with elastomer, such as polyurethane, there is provided a nozzle used for dispensing the liquid polyurethane onto the rotating body to be coated. The nozzle of the invention has a plurality of liquid-flow interior discharge-passageways each of which has an inlet connected to a sub-branch tube, which sub-branch tube is, in turn, is fluidly connected to a main branch that, in turn, is connected to a main inlet-passageway having the inlet that is directly connected to mixing head. Each discharge-passageway, or exit-passageway, changes in cross-sectional shape along the longitudinal axis thereof from its inlet to its outlet such that the cross-sectional area from the inlet to the outlet thereof gradually and minimally increases, whereby at least substantial laminar flow of the liquid is achieved with the concomitant reduced dwell-time of the liquid therein, in order to reduce in-nozzle reaction and subsequent clogging of the nozzle. The exit of the nozzle itself is constituted by the plurality of spaced-apart exit-openings or outlets of the discharge-passageways, where each such exit-opening or outlet is formed as a narrow, elongated slit or opening.