Valve apparatus

Abstract

A valve apparatus that has a longitudinal axis therethrough comprises a valve seat member, a valve closure member, a fluid flow path, and a screening member. The valve seat member comprises a hollow bore and a first frustoconical contact surface. The valve closure member comprises a body and a second frustoconical contact surface that is adapted to seal against the first frustoconical contact surface. The valve closure member is movable along the longitudinal axis of the valve apparatus. The fluid flow path extends through the bore of the valve seat member and between the valve seat member and the valve closure member. This fluid flow path is closed when the second frustoconical contact surface is sealed against the first frustoconical contact surface. The screening member is attached to at least one of the valve closure member or the valve seat member, and screens particles from fluid passing through the fluid flow path when the valve closure member approaches the valve seat member.

1 . A valve apparatus having a longitudinal axis therethrough, comprising: 
 a valve seat member that comprises a hollow bore and a first frustoconical contact surface;    a valve closure member that comprises a body and a second frustoconical contact surface that is adapted to seal against the first frustoconical contact surface, the valve closure member being movable along the longitudinal axis of the valve apparatus;    a fluid flow path through the bore of the valve seat member and between the valve seat member and the valve closure member, the fluid flow path being closed when the second frustoconical contact surface is in contact with the first frustoconical contact surface; and    a forward screening member that is attached to at least one of the valve closure member or the valve seat member and that screens particles and excludes them from fluid passing in a forward direction into the region between the valve seat member and the valve closure member, when the valve closure member approaches the valve seat member.    
   
   
       2 . The valve apparatus of  claim 1 , wherein the forward screening member comprises a plug that is attached to the valve closure member and that extends into the bore of the valve seat member when the valve is closed.  
   
   
       3 . The valve apparatus of  claim 2 , wherein the valve seat member comprises a cylindrical inner wall, and a screening gap exists between the cylindrical inner wall and the plug and the screening gap is small enough to prevent passage of particles of a selected size from passing through the fluid flow path when the plug extends into the bore of the valve seat member.  
   
   
       4 . The valve apparatus of  claim 3 , wherein the plug comprises a first section having a circular bottom of a first diameter and a second section having a circular bottom of second diameter that is greater than the first diameter, and wherein the screening gap between the second section and the cylindrical inner wall is small enough to prevent particles of a selected size from passing through the fluid flow path when the second cylindrical section extends into the bore of the valve seat member.  
   
   
       5 . The valve apparatus of  claim 1 , wherein at least one of the valve closure member and the valve seat member comprises a resilient insert located near the inner perimeter of a frustoconical contact surface.  
   
   
       6 . The valve apparatus of  claim 5 , wherein the resilient insert is attached to the valve closure member and extends further toward the first frustoconical contact surface than the second frustoconical contact surface does.  
   
   
       7 . The valve apparatus of  claim 1 , wherein the forward screening member comprises a forward screening insert that is near the inner perimeter of either the first or second frustoconical contact surface, and wherein a screening gap exists between the forward screening insert and the opposing frustoconical contact surface, and the screening gap becomes small enough to prevent particles of a selected size from passing into the valve assembly before the valve closes far enough to trap particles between the frustoconical contact surfaces.  
   
   
       8 . The valve apparatus of  claim 7 , wherein the forward screening insert is a resilient screening insert.  
   
   
       9 . The valve apparatus of  claim 7 , wherein the forward screening member comprises a plurality of forward screening inserts near the inner perimeter of either the first or second or both frustoconical contact surfaces.  
   
   
       10 . The valve apparatus of  claim 8 , wherein the resilient forward screening insert is attached to the valve seat member and contacts the second frustoconical contact surface when the valve closure member approaches the valve seat member.  
   
   
       11 . The valve apparatus of  claim 8 , wherein the forward screening insert is attached to the valve closure member.  
   
   
       12 . The valve apparatus of  claim 11 , wherein the forward screening insert extends into the bore of the valve seat member when the valve is closed.  
   
   
       13 . The valve apparatus of  claim 9 , wherein at least one of the forward screening inserts extends into the bore of the valve seat member when the valve is closed.  
   
   
       14 - 38 . (canceled)