Flow tube for use in subsurface valves

Abstract

According to one or more aspects of the present disclosure, an engaging member for operating a subsurface valve between an open position and a closed position includes a bottom portion comprising a terminal end adapted for contacting a valve closure member, the bottom portion having a first material characteristic and an upper portion having a second material characteristic that is quantitatively different from the first material characteristic. The material characteristics include, without limitation, strength, coefficient of friction, and the modulus of elasticity.

1 . An engaging member for operating a subsurface valve between an open position and a closed position, the engaging member comprising:
 a bottom portion comprising a terminal end adapted for contacting a valve closure member, the bottom portion having a first material characteristic; and   an upper portion having a second material characteristic that is quantitatively different from the first material characteristic.   
     
     
         2 . The engaging member of  claim 1 , wherein the bottom portion is formed of a material different than the material forming the upper portion. 
     
     
         3 . The engaging member of  claim 1 , wherein the bottom portion comprises a material disposed along a surface of the bottom portion. 
     
     
         4 . The engaging member of  claim 3 , wherein the material disposed along the surface of the bottom portion by one selected from the group of welding, coating, and deposition. 
     
     
         5 . The engaging member of  claim 1 , wherein the bottom portion comprises two or more layers of material. 
     
     
         6 . The engaging member of  claim 1 , wherein the bottom portion is a separate member connected to the upper portion by a connection. 
     
     
         7 . The engaging member of  claim 1 , wherein the material characteristic comprises strength, and the first material characteristic is greater than the second material characteristic. 
     
     
         8 . A subsurface valve configured to move between an open position and a closed position in response to an applied signal, the valve comprising:
 a housing having a bore;   a closure member disposed with the housing;   a flow tube movably disposed in the housing, the flow tube comprising a terminal end positioned to contact the closure member, wherein the closure member is actuated to the open position in response to a certain force applied to the flow tube and actuated to the closed position upon relief of the certain applied force; and   a bottom portion of the flow tube proximate the terminal end comprising a first material characteristic that is quantitatively different than a second material characteristic of an upper portion of the flow tube.   
     
     
         9 . The subsurface valve of  claim 8 , wherein the bottom portion and the upper portion are constructed of different materials of construction. 
     
     
         10 . The subsurface valve of  claim 8 , wherein the bottom portion comprises a material disposed along a surface of the bottom portion, wherein the disposed material provides the first material characteristic. 
     
     
         11 . The subsurface valve of  claim 10 , wherein the material characteristic comprises one selected from the group of strength, coefficient of friction, and modulus of elasticity. 
     
     
         12 . The subsurface valve of  claim 11 , wherein the material characteristic comprises strength, and the first material characteristic is greater than the second material characteristic. 
     
     
         13 . The subsurface valve of  claim 8 , wherein the bottom portion comprises two or more layers of material. 
     
     
         14 . The subsurface valve of  claim 13 , wherein at least two of the two or more layers are constructed of the same material. 
     
     
         15 . The subsurface valve of  claim 8 , wherein the bottom portion is a separate member connected to the upper portion by a connection. 
     
     
         16 . The subsurface valve of  claim 8 , wherein the bottom portion is constructed of a plurality of layers of plate material welded together and formed into a tubular shape. 
     
     
         17 . A method for operating a subsurface valve; the method comprising:
 disposing a valve in a wellbore, the valve comprising:
 a housing having a bore; 
 a closure member disposed with the housing; 
 a flow tube movably disposed in the housing, the flow tube comprising a terminal end positioned to contact the closure member; and 
 a bottom portion of the flow tube proximate the terminal end comprising a first material characteristic that is quantitatively different from a second material characteristic of an upper portion of the flow tube; 
   moving the closure member to an open position in response to a certain force being applied to the flow tube; and   moving the closure member to an open position in response to releasing at least a portion of the certain force applied to the flow tube.   
     
     
         18 . The method of  claim 17 , wherein the material characteristic comprises one selected from the group of strength, coefficient of friction, and modulus of elasticity. 
     
     
         19 . The method of  claim 18 , wherein the material characteristic comprises strength, and the first material characteristic is greater than the second material characteristic. 
     
     
         20 . The method of  claim 17 , wherein the bottom portion is constructed of a plurality of layers of plate material welded together and formed into a tubular shape.