Pressure blast pre-filming spray nozzle

A nozzle assembly for a desuperheating device configured for spraying cooling water, the nozzle assembly comprising:

• a nozzle housing having a valve stem bore formed axially therethrough and including a housing inlet and a housing outlet fluidly interconnected by a plurality of housing passages spaced about the valve stem bore for providing a flow of the cooling water from the housing inlet to the housing outlet, the housing outlet defining an outwardly angled conical valve seat;
• and
• a valve element having an elongate valve stem extending from a truncated conical valve body including a conical outer surface and a concave inner surface a portion of the conical valve body extending downstream of the valve seat, the valve stem being axially slidable within the valve stem bore between a closed and an open position, the inner and outer surfaces collectively defining a body wall with a plurality of angularly spaced-apart valve apertures extending between and fluidly connecting the outer surface to the inner surface, the apertures being provided within the portion of the conical valve body that extends downstream of the valve seat the outer surface being configured to be complementary to the valve seat with the outer surface being sealingly engagable thereto such that the flow of cooling water through the valve apertures is prevented when the valve element is in the closed position;
• wherein the outer surface and the valve seat collectively define an annular gap when the valve element is axially displaced to allow a portion of the cooling water flowing through the annular gap to coat the outer surface and subsequently pass through the valve apertures such that the cooling water exiting the nozzle assembly defines a substantially uniformly distributed conically-shaped spray pattern.