FLUID FLOW DEVICE THAT PROVIDES AN IMPROVED SEAL BY EXPLOITING DIFFERENTIAL THERMAL EXPANSION

摘要

A fluid flow control device includes a valve body, a valve seat disposed within the valve body, and a valve cage coupled to the valve seat within the valve body. The fluid flow control device also includes a gland defined by the valve body, the valve seat, and the valve cage. The valve body has a first thermal expansion coefficient and the valve seat and/or the valve cage have a second thermal expansion coefficient different from the first thermal expansion coefficient. The fluid flow control device further includes a sealing assembly disposed within the fluid flow control device to provide a seal between the valve body and the valve cage. The sealing assembly exploits differential thermal expansion between the valve body and the valve cage in a direction parallel to the longitudinal axis and in a direction transverse to the longitudinal axis to improve the seal.

主权项

1. A fluid flow control device comprising:
a valve body defining an inlet, an outlet, a fluid flow path extending between the inlet and the outlet, and a longitudinal axis, the valve body having a first thermal expansion coefficient; a valve seat disposed within the valve body and defining an orifice through which the fluid flow path passes; a valve cage coupled to the valve seat within the valve body and defining an interior bore, the cage having a second thermal expansion coefficient different than the first thermal expansion coefficient; a valve plug sized for insertion into the interior bore of the valve cage and movable along an axis between a closed position, in which the valve plug engages the valve seat, and an open position; a gland defined by at least one of the valve seat and the valve cage; and a sealing assembly arranged within the gland to provide a seal between the valve body and the valve cage, the sealing assembly arranged in a first compression state in which the sealing assembly provides first radial and axial compression forces, the sealing assembly movable to a second compression state in which the sealing assembly provides second radial and axial compression forces greater than the first radial and axial compression forces, the movement of the sealing assembly being due to differential thermal expansion between the valve body and the valve cage in an axial direction that is parallel to the longitudinal axis and in a radial direction that is transverse to the longitudinal axis.