Patent 7461829 was granted and assigned to Outotec on December, 2008 by the United States Patent and Trademark Office.
The invention relates to a seal to be used as a valve stem seal in a valve for controlling flows containing solid material such as slurry flows with an actuator. The seal is positioned outside of the valve body so that the inside of the seal and the valve body form an essentially closed space for the flow to be controlled.