Method and Apparatus for Through-Cut Verification

Abstract

A method and apparatus for verifying the complete cut through of a tubular member by a fluid cut through device. A follower runs in the kerf created in the tubular member by the fluid cut through device until the follower encounters an incomplete cut, or hanger. The follower rotates away from the fluid cut through device when the follower encounters a hanger, thereby disengaging a switch to interrupt the fluid cut through device.

1 . A method for verifying complete cut-through in a tubular member, the method comprising:
 providing a fluid jet cut through device that cuts a kerf in the tubular member as it is rotated;   providing a switch attached to the jet cut through device;   providing a follower, the follower swively mounted near the switch such that the follower may extend into the kerf created by the fluid cut through device while also engaging the switch; and   rotating the fluid jet cut through device in a direction to create a kerf.   
     
     
         2 . The method of  claim 1  further comprising:
 discontinuing the operation of the fluid cut through device when the follower engages a section of kerf that is incompletely cut. 
 
     
     
         3 . The method of  claim 1  further comprising:
 disengaging the switch when the follower engages a section of kerf that is incompletely cut. 
 
     
     
         4 . The method of  claim 1  further comprising:
 disengaging the switch when the follower engages a section of kerf that is incompletely cut; and 
 discontinuing the operation of the fluid cut through device when the switch is disengaged. 
 
     
     
         5 . The method of  claim 4  further comprising:
 reversing the direction of the fluid cut through device. 
 
     
     
         6 . The method of  claim 4  further comprising:
 reversing the rotation of the fluid cut through device until the follower engages the switch; 
 restarting rotation in the direction of the cut through device. 
 
     
     
         7 . The method of  claim 4  further comprising:
 reversing the rotation of the fluid cut through device such that the follower does not engage the switch; 
 retrieving the fluid cut through device; and 
 replacing the follower. 
 
     
     
         8 . A device for verifying complete cut-through in a tubular member, the device comprising:
 a fluid jet cut through device that cuts a kerf in the tubular member as it is rotated;   a switch attached to the jet cut through device; and   a follower, the follower swively mounted near the switch such that the follower may extend into the kerf created by the fluid cut through device while also engaging the switch.   
     
     
         9 . The device of  claim 8  wherein:
 the follower is a removable member. 
 
     
     
         10 . The device of  claim 9  wherein:
 the removable member is a blade 
 
     
     
         11 . The device of  claim 9  wherein:
 the removable member is a loop. 
 
     
     
         12 . The device of  claim 8  wherein:
 the follower engages the switch while rotating freely in the kerf and disengages the switch when encountering an incompletely cut kerf. 
 
     
     
         13 . The device of  claim 8  wherein:
 the fluid cut through device is mounted on parallel arms to a structure allowing the deployment and retrieval of the fluid cut through device.