Patent ID: 7559531

Claim:
A ball valve, comprising: a valve body defining a flow passage having an upstream flow-through end thereof, a downstream flow-through end thereof and a valve receiving chamber therebetween; a valve member disposed within the valve receiving chamber and having a throughbore therein, the valve member being selectively movable within the valve receiving chamber between an open and a closed position, the open position providing flow-through alignment of the throughbore with the upstream and downstream flow-through ends of the valve body, and the closed position providing an out of flow-through alignment of the throughbore with the upstream and downstream flow-through ends of the valve body for blocking flow through the flow passage; and an upstream seal and a downstream seal operatively connecting the valve member to the valve body at upstream and downstream ends respectively of the valve receiving chamber; and wherein at least the upstream seal includes a spring member positioned between the upstream flow-through end and the upstream seal to provide a bias sealing force against the valve member; wherein at least the upstream seal further includes an o-ring interposed between the spring member and the upstream seal; wherein at least the upstream seal includes a ramped back surface, wherein the ramped back surface and the valve receiving chamber form a dynamic sealing chamber, and wherein the o-ring and the spring member are accommodated in the dynamic sealing chamber; and wherein the o-ring is moved along the ramped back surface upon an increase in pressure in the dynamic sealing chamber to increase a sealing pressure on the valve member.