Abstract: A downstream ball valve purging inlet directs purging fluid intentionally onto a downstream portion of the valve ball. The Coanda effect attaches some of the fluid to the ball's surface, so that it flows around the ball to an opposite side thereof, thereby purging the downstream valve cavity more efficiently than designs that avoid impacting the ball and depend on mixing to distribute the purging fluid onto the ball. The purging inlet can be downstream of the ball and directed at an acute angle, proximate the ball and directed perpendicular to the outlet axis, or some combination thereof. A central cavity purging drain can be connected with the purging inlet, so that the same fluid purges both the valve interior and the downstream cavity. Embodiments include a plurality of downstream purging inlets, which can have equal purging angles and can be equally spaced about the outlet axes.

Abstract: A downstream ball valve purging inlet directs purging fluid intentionally onto a downstream portion of the valve ball. The Coanda effect attaches some of the fluid to the ball's surface, so that it flows around the ball to an opposite side thereof, thereby purging the downstream valve cavity more efficiently than designs that avoid impacting the ball and depend on mixing to distribute the purging fluid onto the ball. The purging inlet can be downstream of the ball and directed at an acute angle, proximate the ball and directed perpendicular to the outlet axis, or some combination thereof. A central cavity purging drain can be connected with the purging inlet, so that the same fluid purges both the valve interior and the downstream cavity. Embodiments include a plurality of downstream purging inlets, which can have equal purging angles and can be equally spaced about the outlet axes.