Low friction live-loaded packing
AssigneeFisher Controls International LLC
InventorsMichel Ken Lovell, Ted Dennis Grabau
Life of this patent
Estimating the term…
Abstract
A valve packing assembly for a control valve includes a seal assembly, a loading assembly, and a packing retainer. The seal assembly has a seal component to provide a fluid seal around a valve stem and an anti-extrusion component to substantially prevent extrusion of the seal component about the valve stem. The loading assembly is configured to advantageously provide a predetermined packing stress to the seal assembly that is in the same direction as a process stress applied to the seal assembly by a process fluid, thereby substantially reducing packing friction and packing wear in the control valve assembly.
Claims16
A cartridge packing assembly to seal a valve stem in a control valve assembly, the cartridge packing assembly comprising:
- a seal assembly having a seal component to provide a fluid seal around the valve stem and at least a first anti-extrusion component to substantially prevent extrusion of the seal member about the valve stem;
- a loading assembly having a loading means comprising at least one spring to provide a predetermined packing stress upon the seal assembly and at least one spacer to couple the at least one spring to the seal assembly;
- and
- a one-piece packing retainer adapted to be disposed in an outboard packing box of the control valve assembly, the packing retainer including a cylindrical sleeve portion defining a packing bore receiving the seal assembly and the loading assembly wherein the one-piece packing retainer includes a fixed length between a retainer shoulder and a loading means seating surface to control a loading assembly force that defines the predetermined packing stress in the control valve assembly, the loading means seating surface extending radially inward from the sleeve portion and the retainer shoulder extending radially outward from the sleeve portion for locating the packing retainer relative to the control valve assembly;
- and
- a bonnet defining the outboard packing box, wherein the packing retainer is removably disposed in the outboard packing box of the bonnet.
Dependencies are inferred from the claim text.