Patent ID: 9218005
Filing Date: 2015-12-22
Classification: F16K,Y10T

Abstract:
1. A trim assembly, comprising: a cage with an interior surface and a cage port; a plug disposed in the cage, the plug having an external surface and being operable between a closed position, a pressure balancing position, and an open position; a low friction flow restrictor disposed between the cage and the plug; a pressure energized seal disposed between the cage and the plug; a seal balancing volume; a pressure control assembly configured to pressurize the seal balancing volume; and a conduit in fluid communication with a volume at an upstream pressure when the plug is in the pressure balancing position, wherein the pressure control assembly is configured to allow fluid at the upstream pressure to flow into the seal balancing volume at a rate in which leakage of fluid through the low friction flow restrictor is less than flow of fluid into the seal balancing volume.