| 摘要 |
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 outlet of the nozzle is a narrow, elongated slit or opening. However, the interior passageway of the nozzle continually changes shape from the inlet (54) to the outlet (52) thereof, in order to ensure a constant cross-sectional area of the interior passageway (50) along the length thereof, and in order to arrive at the desired narrow, elongated outlet-opening, whereby laminar flow of the liquid polyurethane is achieved with the concomitant reduced dwell-time of the liquid polyurethane therein, in order to reduce build up and clogging of the nozzle. Each discharge-passageway, or exit-passageway, also 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.
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