Unitary Flapper Base Method of Manufacture

Abstract

A flapper base provides a flapper base body with a hinge portion unitarily formed thereupon and a flapper seat surface formed within the flowbore of the body. The flapper base may be formed from a single section of tubular metallic stock. In a method of forming a base, the stock is gripped by a rotary clamp, and a five-axis milling machine is used to cut away portions of the stock section and to form the seat surface.

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         5 . A method of making a flapper valve base for a flapper valve, the method comprising the steps of:
 gripping a section of tubular stock within a clamp, the stock section having an axial end and defining an axial flowbore with a longitudinal axis;   cutting away portions of the stock section to at least partially form a hinge retainer portion of the body to which a flapper member will be pivotally secured; and   forming a flapper seat surface within the flowbore against which a flapper member will close.   
     
     
         6 . The method of  claim 5  wherein the flapper seat surface is formed by a five-axis milling machine. 
     
     
         7 . The method of  claim 6  wherein the five-axis milling machine includes a right-angle head which retains a cutting member at an angle that is substantially orthogonal to the longitudinal axis of the stock section. 
     
     
         8 . The method of  claim 7  wherein the cutting member is directed radially outwardly from the longitudinal axis. 
     
     
         9 . The method of  claim 5  wherein the clamp is a rotatable clamp and wherein the stock section is rotated by the clamp about the longitudinal axis during forming of the flapper seat surface. 
     
     
         10 . The method of  claim 5  further comprising the step of forming a groove within the flapper seat surface for retaining a resilient seal. 
     
     
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         16 . A method of making a flapper valve base for a flapper valve, the method comprising the steps of:
 providing a section of tubular stock defining an axial flowbore with a longitudinal axis; and   milling an interior surface of the flowbore to remove material from the interior surface to form a seat surface within the flowbore against which a flapper member will close.   
     
     
         17 . The method of  claim 16  further comprising the step of cutting away portions of an axial end of the stock section to at least partially form a hinge retainer portion of the body to which a flapper member will be pivotally secured. 
     
     
         18 . The method of  claim 16  wherein the seat surface is formed by a five-axis milling machine. 
     
     
         19 . The method of  claim 16  wherein the seat surface is formed by a cutting member that is disposed radially outwardly at an angle that is orthogonal to the longitudinal axis. 
     
     
         20 . The method of  claim 16  wherein the seat surface is formed in a sine-wave configuration. 
     
     
         21 . The method of  claim 16  further comprising the step of forming a groove within the seat surface for retaining a resilient seal. 
     
     
         22 . The method of  claim 16  further comprising the step of forming threads within the stock section. 
     
     
         23 . The method of  claim 16  wherein the stock section is gripped by a rotatable clamp and wherein the stock section is rotated by the clamp about the longitudinal axis during forming of the seat surface. 
     
     
         24 . A method of making a flapper valve base for a flapper valve, the method comprising the steps of:
 providing a section of tubular stock having an axial flowbore with a longitudinal axis;   milling an interior surface of the flowbore to remove material from the interior surface to form a seat surface within the flowbore against which a flapper member will close; and   forming a groove within the seat surface for retaining a resilient seal.   
     
     
         25 . The method of  claim 24  further comprising the step of cutting away portions of an axial end of the stock section to at least partially form a hinge retainer portion of the body to which a flapper member will be pivotally secured. 
     
     
         26 . The method of  claim 24  wherein the seat surface is formed in a sine-wave configuration. 
     
     
         27 . The method of  claim 24  further comprising the step of forming a groove within the seat surface for retaining a resilient seal. 
     
     
         28 . The method of  claim 24  wherein the seat surface is formed by a five-axis milling machine. 
     
     
         29 . The method of  claim 24  wherein the stock section is gripped by a rotatable clamp and wherein the stock section is rotated by the clamp about the longitudinal axis during forming of the seat surface.