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 plug-and-seat valve plug head assembly that resists abrasive erosion includes a hardened plug head, such as a ceramic plug head, attached to a plug stem without any soldering, welding, or braising attachment to the plug head. A diameter of a second portion of the plug head smoothly increases according to a plug diameter profile. A diameter of a first portion of the plug head is everywhere smaller than the plug diameter profile, and is maximal at a location spaced apart from the second portion. A plug head retainer overlaps and closely conforms to the first portion, while presenting an exterior surface that smoothly continues and extends the plug diameter profile. In embodiments, a plug head retainer blank attaches to the plug head retainer, capturing the plug head therebetween. Embodiments apply radial and/or axial stress to the plug head.

Abstract: A technique for reducing the risk of free flow through a pump is disclosed. The technique includes sensing a pressure difference between the pump inlet and outlet. The pressure difference is mechanically communicated to a flow restricting element. The flow restricting element increases resistance to flow exiting the pump outlet in a relation to the pressure difference present between the pump inlet and pump outlet.

Abstract: A technique for reducing the risk of free flow through a pump is disclosed. The technique includes sensing a pressure difference between the pump inlet and outlet. The pressure difference is mechanically communicated to a flow restricting element. The flow restricting element increases resistance to flow exiting the pump outlet in a relation to the pressure difference present between the pump inlet and pump outlet.