Valve seat apparatus for use with fluid valves

Abstract

A valve seat apparatus for use with fluid valves is described herein. An example valve seat apparatus includes a seat ring having a central passage therethrough and an outer wall. The outer wall comprises a threaded portion, having a first diameter, to engage a cage of a fluid valve. The outer wall also includes a sealing portion to capture a seal assembly between the sealing portion and a surface of a body of the fluid valve. The sealing portion has a second diameter greater than the first diameter. The outer wall of the example valve seat apparatus further includes a flange portion to capture the seal assembly between the cage and the flange portion. The flange portion extends toward the surface of the body and the sealing portion is to be positioned between the flange portion and the threaded portion. The flange portion has a third diameter greater than the second diameter.

What is claimed is: 
     
         1 . An apparatus comprising:
 a cage to be disposed in a fluid valve, the cage including:
 a main portion, an inner wall of the main portion having a first inner diameter; and 
 an extension extending from the main portion, an inner wall of the extension having a second inner diameter greater than the first inner diameter; and 
   a seat ring to be coupled to the cage, the seat ring having an outer wall, the outer wall including:
 a threaded portion to engage the cage, the threaded portion having a first outer diameter; 
 a sealing portion to capture a seal assembly between the sealing portion and a surface of a body of the fluid valve, the sealing portion having a second outer diameter greater than the first outer diameter; 
 a flange portion having a third outer diameter greater than the second outer diameter, the sealing portion being between the flange portion and the threaded portion; and 
 a step between the flange portion and the sealing portion, an annular gland being defined by the step, the sealing portion and a bottom surface of the extension when the seat ring is coupled to the cage, the annular gland to receive the seal assembly. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the step is a first step, the outer wall further including a second step between the sealing portion and the threaded portion. 
     
     
         3 . The apparatus of  claim 2 , wherein the cage further includes a shoulder between the inner wall of the main portion and the inner wall of the extension, the shoulder to engage the second step when the seat ring is coupled to the cage. 
     
     
         4 . The apparatus of  claim 1 , wherein the inner wall of the main portion of the cage includes threads to threadably couple with the threaded portion of the outer wall of the seat ring. 
     
     
         5 . The apparatus of  claim 4 , wherein, when the threaded portion of the seat ring is threadably coupled to the main portion of the cage, the inner wall of the extension extends along the sealing portion of the outer wall of the seat ring. 
     
     
         6 . The apparatus of  claim 1 , wherein the seal assembly is a first seal assembly, and wherein the first seal assembly is interchangeable with a second seal assembly different from the first seal assembly. 
     
     
         7 . The apparatus of  claim 6 , wherein the first seal assembly includes a polytetrafluoroethylene seal and the second seal assembly includes a metal seal having a C-shaped cross-section 
     
     
         8 . The apparatus of  claim 6 , wherein the first seal assembly is for use with process fluids having temperatures less than 600° F. and the second seal assembly is for use with process fluids having temperatures greater than about 600° F. 
     
     
         9 . An apparatus comprising:
 a cage to be disposed in a fluid valve, the cage including:
 a main portion, an inner wall of the main portion having a first inner diameter, the inner wall of the main portion having first threads; and 
 an extension extending from the main portion, an inner wall of the extension having a second inner diameter greater than the first inner diameter; and 
   a seat ring to be coupled to the cage, the seat ring including:
 a first portion, an outer wall of the first portion having a first outer diameter, the outer wall of the first portion having second threads to be threadably coupled to the first threads; 
 a second portion, the outer wall of the second portion having a second outer diameter greater than the first outer diameter; and 
 a third portion, an outer wall of the third portion having a third outer diameter greater than the second outer diameter, the second portion positioned between the third portion and the first portion. 
   
     
     
         10 . The apparatus of  claim 9 , wherein, when the seat ring is coupled to the cage, the inner wall of the extension and the outer wall of the second portion are parallel and facing each other. 
     
     
         11 . The apparatus of  claim 9 , wherein the seat ring is a substantially unitary piece or structure. 
     
     
         12 . The apparatus of  claim 9 , wherein the seat ring includes a step between the outer wall of the second portion and the outer wall of the third portion. 
     
     
         13 . The apparatus of  claim 12 , wherein, when the seat ring is coupled to the cage, a seal gland is formed by the outer wall of the second section, a bottom surface of the extension, a surface of the fluid valve, and the step. 
     
     
         14 . The apparatus of  claim 13 , further including means for sealing, the means for sealing disposed within the seal gland. 
     
     
         15 . An apparatus comprising:
 a cage to be disposed in a fluid valve, the cage including:
 a main portion, an inner wall of the main portion having a first inner diameter; and 
 an extension extending from the main portion, an inner wall of the extension having a second inner diameter greater than the first inner diameter; and 
   a seat ring to be coupled to the cage, the seat ring having an outer wall, the outer wall including:
 a threaded portion to be threadably coupled to the cage, the threaded portion having a first outer diameter; 
 a sealing portion to capture a seal assembly between the sealing portion and a surface of a body of the fluid valve, the sealing portion having a second outer diameter greater than the first outer diameter; 
 a flange portion having a third outer diameter greater than the second outer diameter, the sealing portion positioned between the flange portion and the threaded portion; and 
 a step between the sealing portion and the flange portion, wherein the seat ring is to be threaded onto the cage to capture the seal assembly between the step and a bottom surface of the extension. 
   
     
     
         16 . The apparatus of  claim 15 , wherein, when the seat ring is coupled to the cage, a cavity is formed between the sealing portion, the bottom surface of the extension, the body of the fluid valve, and the step, the seal assembly disposed in the cavity. 
     
     
         17 . The apparatus of  claim 15 , wherein the first inner diameter is substantially the same as the first outer diameter, and the second inner diameter is substantially the same as the second outer diameter. 
     
     
         18 . The apparatus of  claim 15 , wherein, to remove the seal assembly, the seat ring is to be unthreaded from the cage. 
     
     
         19 . The apparatus of  claim 15 , wherein the seal assembly is a first seal assembly, and wherein the first seal assembly is interchangeable with a second seal assembly different from the first seal assembly. 
     
     
         20 . The apparatus of  claim 15 , wherein the seal assembly includes at least one of a cryogenic seal, a polytetrafluoroethylene seal, an anti-extrusion ring, an omni-seal, a flat gasket, a spring-loaded seal or a c-seal.